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Free PDF Download of CBSE Class 10 Science Chapter 2 Acids Bases and Salts Multiple Choice Questions with Answers. MCQ Questions for Class 10 Science with Answers was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 10 Science Acids Bases and Salts Multiple Choice Questions with Answers to know their preparation level.

Class 10 Science MCQs Chapter 2 Acids Bases and Salts

1. What happens when a solution of an acid is mixed with a solution of a base in a test tube?
(i) Temperature of the solution decreases
(ii) Temperature of the solution increases
(in) Temperature of the solution remains the same
(iv) Salt formation takes place
(a) (i) and (iv)
(b) (i) and (iii)
(c) (ii) only
(d) (ii) and (iv)

Answer

Answer: d

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2. When hydrogen chloride gas is prepared on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to
(a) absorb the evolved gas
(b) moisten the gas
(c) absorb moisture from the gas
(d) absorb Cl^– ions from the evolved gas

Answer/ Explanation

Answer: c
Explaination: Reason: Guard tube drys (absorbs water) from calcium chloride on a humid day.

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3. Which one of the following salts does not con-tain water of crystallisation?
(a) Blue vitriol
(b) Baking soda
(c) Washing soda
(d) Gypsum

Answer

Answer: b

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4. In terms of acidic strength, which one of the following is in the correct increasing order?
(a) Water < Acetic acid < Hydrochloric acid
(b) Water < Hydrochloric acid < Acetic acid
(c) Acetic acid < Water < Hydrochloric acid
(d) Hydrochloric acid < Water < Acetic acid

Answer

Answer: a

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5. What is formed when zinc reacts with sodium hydroxide?
(a) Zinc hydroxide and sodium
(b) Sodium zincate and hydrogen gas
(c) Sodium zinc-oxide and hydrogen gas
(d) Sodium zincate and water

Answer/ Explanation

Answer: b
Explaination: Reason: Zn + 2NaOH → Ma₂Zn0₂ (Sodium Zincate) + H₂

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6. Tomato is a natural source of which acid?
(a) Acetic acid
(b) Citric acid
(c) Tartaric acid
(d) Oxalic acid

Answer

Answer: d

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7. Brine is an
(a) aqueous solution of sodium hydroxide
(b) aqueous solution of sodium carbonate
(c) aqueous solution of sodium chloride
(d) aqueous solution of sodium bicarbonate

Answer

Answer: c

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8. Na₂CO₃ . 10H₂O is
(a) washing soda
(b) baking soda
(c) bleaching powder
(d) tartaric acid

Answer

Answer: a

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9. At what temperature is gypsum heated to form Plaster of Paris?
(a) 90°C
(b) 100°C
(c) 110°C
(d) 120°C

Answer

Answer: b

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10. How many water molecules does hydrated cal-cium sulphate contain?
(a) 5
(b) 10
(c) 7
(d) 2

Answer/ Explanation

Answer: d
Explaination: Reason: Chemical formula of hydrated calcium sulphate or gypsum is CaSO₄.2H₂O

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11. Sodium carbonate is a basic salt because it is a salt of a
(a) strong acid and strong base
(b) weak acid and weak base
(c) strong acid and weak base
(d) weak acid and strong base

Answer

Answer: d

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12. Alkalis are
(a) acids, which are soluble in water
(b) acids, which are insoluble in water
(c) bases, which are insoluble in water
(d) bases, which are soluble in water

Answer

Answer: d

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13. Which of the following statements is correct about an aqueous solution of an acid and of a base?
(i) Higher the pH, stronger the acid
(ii) Higher the pH, weaker the acid
(in) Lower the pH, stronger the base
(iv) Lower the pH, weaker the base
(a) (i) and (iii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (ii) and (iv)

Answer/ Explanation

Answer: d
Explaination: Reason: Stronger the acid, lesser is the pH. Stronger the base, higher is the pH.

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14. The apparatus given in the adjoining figure was set up to demonstrate electrical conductivity.

Which of the following statement(s) is (are) correct?
(i) Bulb will not glow because electrolyte is not acidic.
(ii) Bulb will glow because HCl is a strong acid and furnishes ions for conduction.
(iii) Bulb will not glow because circuit is incomplete.
(iv) Bulb will not glow because it depends upon the type of electrolytic solution.
(a) (i) and (iii)
(b) (ii) and (iv)
(c) (ii) only
(d) (iv) only

Answer

Answer: c

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15. Lime water reacts with chlorine to give
(a) bleaching powder
(b) baking powder
(c) baking soda
(d) washing soda

Answer/ Explanation

Answer: c
Explaination:

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16. Nettle sting is a natural source of which acid?
(a) MetiWanoic acid
(b) Lactic acid
(c) Citric acid
(d) Tartaric acid

Answer

Answer: a

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17. Tooth enamel is made up of
(a) calcium phosphate
(b) calcium carbonate
(c) calcium oxide
(d) potassium

Answer

Answer: a

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18. What is the pH range of our body?
(a) 7.0 – 7.8
(b) 7.2 – 8.0
(c) 7.0 – 8.4
(d) 7.2 – 8.4

Answer

Answer: a

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19. Rain is called acid rain when its:
(a) pH falls below 7
(b) pH falls below 6
(c) pH falls below 5.6
(d) pH is above 7

Answer

Answer: c

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20. Sodium hydroxide is a
(a) weak base
(b) weak acid
(c) strong base
(d) strong acid

Answer/ Explanation

Answer: c
Explaination: Reason: Sodium hydroxide ionises in water and produces a large amount of hydroxide ions.

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21. An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?
(a) Baking powder
(b) Lime
(c) Ammonium hydroxide solution
(d) Hydrochloric acid

Answer

Answer: d

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22. When copper oxide and dilute hydrochloric acid react, colour changes to
(a) white
(b) bluish-green
(c) blue-black
(d) black

Answer/ Explanation

Answer: b
Explaination: Reason: Blue-green colour of solution is due to the formation of copper (II) chloride.

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23. Sodium hydroxide is used
(a) as an antacid
(b) in manufacture of soap
(c) as a cleansing agent
(d) in alkaline batteries

Answer

Answer: b

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24. Sodium hydroxide turns phenolphthalein solution
(a) pink
(b) yellow
(c) colourless
(d) orange

Answer

Answer: a

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25. Chemical formula of washing soda is
(a) Na₂C0₃ . 7H₂O
(b) Na₂C0₃ . 5H₂O
(c) Na₂C0₃ . 2H₂O
(d) Na₂C0₃ . 10H₂O

Answer

Answer: d

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26. Which of the following is not a acidic salt?
(a) CuSO₄
(b) NH₄Cl
(c) FeCl₃
(d) CH₃COONa

Answer

Answer: d

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27. A solution of NaCl
(i) will turn red litmus blue
(ii) will turn pH paper green
(iii) will turn blue litmus red
(iv) will not affect litmus
(a) (i) and (ii)
(b) (i), and, (iii)
(c) (i) and (iv)
(d) (ii) and (iv)

Answer

Answer: d

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28. Many salts absorbs water from atmosphere. This property is called
(a) deliquescence
(b) efflorescence
(c) hydration
(d) addition

Answer

Answer: a

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29. An aqueous solution with pH = 1 is
(a) strongly acidic
(b) strongly basic
(c) neutral
(d) weakly acidic

Answer

Answer: a

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30. CaOCl2 will liberate Cl₂ gas in presence of
(i) CO₂
(ii) HCl
(iii) CO
(iv) NO
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (ii) and (iv)

Answer

Answer: a

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31. Egg shell is made up of
(a) CaCO₃
(b) CaO
(c) Ca(OH)₂
(d) CaCl₂

Answer

Answer: a

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32. Curd cannot be stored in
(z) Brass vessel
(ii) Copper vessel
(iii) Steel
(iv) Bronze
(a) (i), (ii), (iii)
(b) (ii), (iii), (iv)
(c) (i), (ii), (iv)
(d) (i), (iii), (iv)

Answer

Answer: c

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33. What happens when a solution of an acid is mixed with a solution of a base in a test tube? [NCERT Exemplar Problems]
(i) The temperature of the solution increases
(ii) The temperature of the solution decreases
(iii) The temperature of the solution remains the same
(iv) Salt formation takes place.
(a) (i) only
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (i) and (iv)

Answer

Answer: d

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34. An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change? [NCERT Exemplar Problems]
(a) Baking power
(b) Lime
(c) Ammonium hydroxide solution
(d) Hydrochloric acid

Answer

Answer: d

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35. During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to [NCERT Exemplar Problems]
(a) absorb the evolved gas
(b) moisten the gas
(c) absorb moisture from the gas
(d) absorb CL ions from the evolved gas

Answer

Answer: c

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36. Which of the following salts does not contain water of crystallisation? [NCERT Exemplar Problems]
(a) Blue vitriol
(b) Baking soda
(c) Washing soda
(d) Gypsum

Answer

Answer: b

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37. Sodium carbonate is a basic salt because it is a salt of [NCERT Exemplar Problems]
(a) strong acid and strong base.
(b) weak acid and weak base.
(c) strong acid and weak base.
(d) weak acid and strong base.

Answer

Answer: d

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38. Calcium phosphate is present in tooth enamel. Its nature is [NCERT Exemplar Problems]
(a) basic
(b) acidic
(c) neutral
(d) amphoteric

Answer

Answer: a

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39. A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue? [NCERT Exemplar Problems]
(a) Lemon juice
(b) Vinegar
(c) Common salt
(d) An antacid

Answer

Answer: d

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40. Which of the following gives the correct increasing order of acidic strength ? [NCERT Exemplar Problems]
(a) Water < Acetic acid < Hydrochloric acid
(b) Water < Hydrochloric acid < Acetic acid
(c) Acetic acid < Water < Hydrochloric acid
(d) Hydrochloric acid < Water < Acetic acid

Answer

Answer: a

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41. Which of the following phenomena occur, when a small amount of acid is added to water ?

Answer

Answer: b

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42. Which one of the following can be used as an acid-base indicator by a visually impared (blind) student ?
(a) Litmus
(b) Turmeric
(c) Vanilla essence
(d) Petunia leaves

Answer

Answer: c

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43. In an attempt to demonstrate electrical conductivity through an electrolyte, the following apparatus was set up.

Which among the following statement)s) is (are) correct?
(i) Bulb will not glow because electrolyte is not acidic.
(ii) Bulb will glow because NaOH is a strong base and furnishes ions for conduction.
(iii) Bulb will not glow because circuit is incomplete.
(iv) Bulb will not glow because it depends upon the type of electrolytic solution.
(a) (i) and (iii)
(b) (ii) and (iv)
(c) (ii) only
(d) (iv) only

Answer

Answer: c

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44. Which of the following is used for dissolution of gold ? [NCERT Exemplar Problems]
(a) Hydrochloric acid
(b) Sulphuric acid
(c) Nitric acid
(d) Aqua regia

Answer

Answer: d

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45. Which among the following is not a base? [NCERT Exemplar Problems]
(a) NaOH
(b) KOH
(c) NH₄OH
(d) C₂H₅OH

Answer

Answer: d

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46. Which of the following statement is not correct? [NCERT Exemplar Problems]
(a) All metal carbonates react with acid to give salt, water and carbon dioxide.
(b) All metal oxides react with water to give salt and acid.
(c) Some metals react with acids to give salt and hydrogen.
(d) Some non-metal oxides react with water to form an acid.

Answer

Answer: b

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47. Equal volumes of hydrochloric acid and sodium hydroxide solutions of same concentration are mixed and the pH of the resulting solution is checked with a pH paper. What would be the colour obtained? (You may use colour guide given in figure)

(a) Red
(b) Yellow
(c) Yellowish green
(d) Blue

Answer

Answer: c

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48. Which of the following is(are) true when HCl (g) is passed through water ? [NCERT Exemplar Problems]
(i) It does not ionise in the solution as it is a covalent compound.
(ii) It ionises in the solution.
(iii) It gives both hydrogen and hydroxyl ion in the solution.
(iv) It forms hydronium ion in the solution due to the combination of hydrogen ion with water molecule.
(a) (i) only
(b) (iii) only
(c) (ii) and (iv)
(d) (iii) and (iv)

Answer

Answer: c

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49. Which of the following statements is true for acids? [NCERT Exemplar Problems]
(a) Bitter and change red litmus to blue.
(b) Sour and change red litmus to blue.
(c) Sour and change blue litmus to red.
(d) Bitter and change blue litmus to red.

Answer

Answer: c

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50. Which of the following are present in a dilute aqueous solution of hydrochloric acid? [NCERT Exemplar Problems]
(a) H₃O⁺ + Cl^–
(b) H₃O⁺ + OH^–
(c) Cl^– + OH^–
(d) unionised HCl

Answer

Answer: a

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51. NaHCO, formed by reaction of
(a) NaOH + H₂CO₃
(b) NaCl + H₂CO₃
(c) Na₂CO₃ + HCl
(d) NaOH + Na₂CO₃

Answer/Explanation

Answer: a
Explanation:
(a) NaOH + H₂CO₃ → NaHCO₃ + H₂O

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52. pH of H₂0 is
(a) 7
(b) 8
(c) 9
(d) 10

Answer/Explanation

Answer: a
Explanation:
(a) pH of H₂O is 7 because it is neutral.

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53. Ag₂S reacts with H₂SO₄ to form
(a) AgSO₄
(b) Ag2SO₄ + H₂S
(c)Ag₂O + H₂S
(d) AgOH + H₂S

Answer/Explanation

Answer: b
Explanation:
(b) Ag₂S + H₂SO₄ → Ag₂SO₄ + H₂S

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54. Lime water reacts with chlorine to form
(a) CaCl₂
(b) CaOCl₂
(c) Ca(ClO₃)₂
(d) CaO₂Cl₂

Answer/Explanation

Answer: b
Explanation:
(b) Ca(OH)₂ + Cl₂ -> CaOCl₂ + H₂O

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55. NaOH is obtained by electrolysis of
(a) Aq. solution of NaCl
(b) Aq. Na₂CO₃
(c) Aq. NaHCO₃
(d) Molten NaCl

Answer/Explanation

Answer: a
Explanation:
(a) 2NaCl + 2H₂O → 2NaOH + H₂ + Cl₂

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Direction (Q56 to Q60): In the following Questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.
(c) Assertion is true but the Reason is false.
(d) The statement of the Assertion is false but the Reason is true.
56. Assertion: Carbonic acid is weak acid
Reason: It ionised completely in aqueous solution.

Answer/Explanation

Answer: c
Explanation:
(c) Assertion is true but the Reason is false.

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57. Assertion: Copper sulphate is acidic salt.
Reason: It is a salt of weak base [Cu(OH)₇] and strong acid (H₇SO₄).

Answer/Explanation

Answer: a
Explanation:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanationof the Assertion.

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58. Assertion: Ammonium hydroxide is Weak Base
Reason: Phenolphthalein becomes pink in NH₂OH

Answer/Explanation

Answer: b
Explanation:
(b) The Assertion and the Reason are correct but the Reason is not the correct explanationof the Assertion.

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59. Assertion: Bleaching power liberate chlorine when kept in atmosphere.
Reason: CaOCl₂ reacts with CO₂ present in atmosphere to form CaCO₃ and chlorine gas.

Answer/Explanation

Answer: a
Explanation:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanationof the Assertion.

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60. Assertion: Universal indicator gives green colour with distilled water.
Reason: pH of distilled water is 7 and it is neutral and universal indicator gives green colour with neutral solution.

Answer/Explanation

Answer: a
Explanation:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanationof the Assertion.

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61. One of the constituents of baking powder is sodium hydrogen carbonate, the other constituent is _____________ .

Answer/Explanation

Answer: a
Explanation: tartaric acid

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62. The three most common indicators to test for acid and bases are litmus _____________ and _____________ .

Answer/Explanation

Answer: a
Explanation: methyl orange, phenolphthalein

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63. Acid reacts with metal to form salt and _____________ gas.

Answer/Explanation

Answer: a
Explanation: hydrogen

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64. The aqueous solution of an acid or a base conducts electricity due to the presence of _____________ in it.

Answer/Explanation

Answer: a
Explanation: ions

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65. A base which is soluble in water is known as an _____________ .

Answer/Explanation

Answer: a
Explanation: alkali

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66. The salts of carbonic acids are called _____________ .

Answer/Explanation

Answer: a
Explanation: carbonates

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67. Methyl orange indicator gives red colour in acidic solution and yellow colour in basic solution. [True/False]

Answer/Explanation

Answer: a
Explanation: True

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68. All the organic acids are strong acids. [True/False]

Answer/Explanation

Answer: a
Explanation: False

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69. The dilution of a concentrated acid should always be done by adding concentrated acid to water gradually with stirring. [True/False]

Answer/Explanation

Answer: a
Explanation: True

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70. Glucose solution conduct electricity. [True/False]

Answer/Explanation

Answer: a
Explanation: False

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71. The strength of an acid or base is measured on a scale of numbers called pH paper. [True/False]

Answer/Explanation

Answer: a
Explanation: False

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72. The more alkaline a solution, the more is the pH. [True/False]

Answer/Explanation

Answer: a
Explanation: True

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Direction (Q48 to Q49): Match Column I with Column II.
73.

Column I	Column II
A. Bleaching powder	(i) Preparation of glass
B. Plaster of Paris	(ii) Production of H2 and Cl2
C. Washing soda	(iii) Manufacture of chalk
D. Baking soda	(iv) Antacid
E. Sodium chloride	(v) Decolourisation

Answer/Explanation

Answer: a
Explanation:
A (v)
B (iii)
C (i)
D (iv)
E (ii)

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74.

Column I	Column II
A. Plaster of Paris	(i) CaSO4 . 2H2O
B. Bleaching powder	(ii) CaO
C. Washing soda	(iii) CaSO4 . 1/2H2O
D. Gypsum	(iv) Na2CO3 . 10H2O
E. Slaked lime	(v) Ca(OH) 2
F. Quick lime	(vi) CaOCl2

Answer/Explanation

Answer: a
Explanation:
A (iii)
B (vi)
C (iv)
D (i)
E (ii)
F (v)

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75. What are indicators?

Answer/Explanation

Answer: a
Explanation:
Those substances which change their colour in different types of substances are called indicators.

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76. What is litmus solution?

Answer/Explanation

Answer: a
Explanation:
It is purple dye which is extracted from a plant ‘lichen’. It is used as acid-base indicator.

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77. Name a salt which does not contain water of crystallisation. [DoE]

Answer/Explanation

Answer: a
Explanation:
Salts like barium sulphate, potassium chloride, sodium nitrate, etc does not contain water of crystallisation.

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78. Define universal indicator.

Answer/Explanation

Answer: a
Explanation:
A universal indicator is a mixture of indicators which shows a gradual but well marked series of colour changes over a very wide range of change in concentration of H⁺ ions.

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79. Name an indicator which indicates the various levels of hydrogen ion concentration.

Answer/Explanation

Answer: a
Explanation: Universal indicator.

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80. Name flowers whose colour or petals can be used as indicator.

Answer/Explanation

Answer: a
Explanation: Hydrangea, Petunia, Geranium

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81. What are phenolphthalein and methyl orange?

Answer/Explanation

Answer: a
Explanation: Synthetic indicators

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82. What is the colour of methyl orange in NaOH?

Answer/Explanation

Answer: a
Explanation: Yellow.

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83. What is the colour of phenolphthalein in milk of magnesia?

Answer/Explanation

Answer: a
Explanation: Pink.

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84. What is the colour of turmeric in soap solution?

Answer/Explanation

Answer: a
Explanation: Reddish-brown.

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85. What will happen to red litmus solution when it is added to bitter gourd extract? Is it acidic or basic?

Answer/Explanation

Answer: a
Explanation: It changes to blue. It is basic in nature.

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86. What will happen to blue litmus when it is added to soda water?

Answer/Explanation

Answer: a
Explanation: It changes to red.

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87. Dry ammonia gas has no action on litmus paper, but a solution of ammonia in water turns red litmus paper blue. Why is it so?

Answer/Explanation

Answer: a
Explanation:
Ammonia dissolves in water, forms ammonium hydroxide which is base and turns red litmus blue.
NH₃ + H₂O → NH₄⁺ + OH^–
Dry ammonia gas does not change into OH^– ions.

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88. What would be the colour of litmus in a solution of sodium carbonate?

Answer/Explanation

Answer: a
Explanation:
The red litmus will change to blue in sodium carbonate solution.

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89. Name an acid-base indicator prepared at home.

Answer/Explanation

Answer: a
Explanation:
Beetroot extract.

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90. What is the colour of litmus in a solution of ammonium hydroxide?

Answer/Explanation

Answer: a
Explanation:
Red litmus will turn blue in ammonium hydroxide.

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91. A bud of petunia became reddish purple after first shower of rain. What does it indicate?

Answer/Explanation

Answer: a
Explanation:
The rain was acid-rain.

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92. How will you test for the gas which is liberated when hydrochloric acid reacts with an active metal? [CBSE 2012]

Answer/Explanation

Answer: a
Explanation:
Bring a burning matchstick near the gas. It bums with ‘pop’ sound showing that it is hydrogen.

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93. Which gas is evolved when sodium hydroge-ncarbonate reacts with dilute hydrochloric acid?

Answer/Explanation

Answer: a
Explanation:
Carbon dioxide gas is evolved.

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94. A few drops of sulphuric acid is added to water before electrolysis, why? [CBSE 2011]

Answer/Explanation

Answer: a
Explanation:
It makes water better conductor.

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95. What effect does the concentration of H⁺(ag) have on the acidic nature of the solution?

Answer/Explanation

Answer: a
Explanation:
Acidic nature increases with increase in cone, of H₃O⁺ ion.

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96. Which planet contains yellowish clouds of sulphuric acid?

Answer/Explanation

Answer: a
Explanation: Venus.

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97. Why does HCl(g) not conduct electricity when dissolved in toluene?

Answer/Explanation

Answer: a
Explanation:
It is because HCl cannot ionise in organic solvent like toluene.

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98. How will you test a gas which is liberated when HCl acid reacts with an active metal? [DoE]

Answer/Explanation

Answer: a
Explanation:
The gas liberated is hydrogen gas. If we bring a burning splinter near the test tube, the splinter will extinguish with a pop sound.

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99. Which gas is evolved when metal carbonates or metal hydrogen carbonate reacts with dilute acids?

Answer/Explanation

Answer: a
Explanation: CO₂(g)

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100. Which acid is present in honey bee sting and hair of nettle leaves?

Answer/Explanation

Answer: a
Explanation: Formic acid

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Fill in the blanks

1. Acids turn …………. litmus solution…………. .
2. pH of basic solution is always …………. than 7.
3. …………. are the products obtained when bleaching powder reacts with dilute sulphuric acid.
4. Potassium nitrate has pH value equal to …………. .
5. …………. is the fixed number of water molecules chemically attached to each formula unit of a salt in its crystalline form.
6. …………. is one of the raw materials for the production of baking soda.
7. The salts of a strong acid and weak base are …………. with pH value …………. than 7.
8. Use of mild base like …………. on the bee-stung area gives relief.
9. During indigestion the stomach produces too much …………. and this causes pain and irritation.
10. The presence of …………. Ca in acids is responsible for their acidic properties.
11. Mixing an acid or base with water results in decrease in the concentration of per unit volume.
This process is called
12. Among HCl, H₂SO₄ and CH₃COOH, …………. is a weak acid.

Answers

1. blue, red
2. more/greater
3. CaSO₄, Cl₂, H₂O
4. 7 or seven
5. Water of crystallisation
6. Sodium chloride
7. acidic, less
8. baking soda
9. acid (HCl)
10. H⁺
11. OH^– ions/H₃O⁺ ions, dilution
12. CH₃COOH

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Free PDF Download of CBSE Class 10 Science Chapter 1 Chemical Reactions and Equations Multiple Choice Questions with Answers. MCQ Questions for Class 10 Science with Answers was Prepared Based on Latest Exam Pattern. Students can solve NCERT Class 10 Science Chemical Reactions and Equations Multiple Choice Questions with Answers to know their preparation level.

Class 10 Science MCQs Chapter 1 Chemical Reactions and Equations

1. Which of the following is a displacement reaction?

Answer/ Explanation

Answer: b
Explaination: Reason: Here sodium (Na) displaces to form sodium hydroxide.

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2. Magnesium ribbon is rubbed before burning because it has a coating of
(a) basic magnesium carbonate
(b) basic magnesium oxide
(c) basic magnesium sulphide
(d) basic magnesium chloride

Answer

Answer: a

---

3. Which of the following statements about the given reaction are correct?
3Fe (s) + 4H₂O (g) → Fe₃O₄ (s) + 4 H₂ (g)
(i) Iron metal is getting oxidised
(ii) Water is getting reduced
(iii) Water is acting as reducing agent
(iv) Water is acting as oxidising agent
(a) (i), (zi) and (iii)
(b) (in) and (iv)
(c) (i), (ii) and (iv)
(d) (ii) and (iv)

Answer

Answer: c

---

4. Which of the following are exothermic processes?
(i) Reaction of water with quick lime
(ii) Dilution of an acid
(iii) Evaporation of water
(iv) Sublimation of camphor (crystals)
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (ii) and (iv)

Answer/ Explanation

Answer: a
Explaination: Reason: In both the cases, heat energy is evolved.

---

5. Oxidation is a process which involves
(a) addition of oxygen
(b) addition of hydrogen
(c) removal of oxygen
(d) removal of hydrogen

Answer

Answer: a

---

6. The process of reduction involves
(a) addition of oxygen
(b) addition of hydrogen
(c) removal of oxygen
(d) removal of hydrogen

Answer

Answer: b

---

7. Three beakers labelled as A, B and C each containing 25 ml of water were taken. A small amount of NaOH, anhydrous CuSO₄ and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solution contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is (are) correct?
(i) In beakers A and B, exothermic process has occurred.
(ii) In beakers A and B, endothermic process has occuBftd.
(iii) In beaker C exothermic process has occurred.
(iv) In beaker C endothermic process has occurred.
(a) (i) only
(b) (ii) only
(c) (i) and (iv)
(d) (iv), (ii) and (iii)

Answer

Answer: c

---

8. Give the ratio in which hydrogen and oxygen are present in water by volume.
(a) 1:2
(b) 1:1
(c) 2:1
(d) 1:8

Answer

Answer: a

---

9. Which among the following statement(s) is (are) true?
Exposure of silver chloride to sunlight for a long duration turns grey due to
(i) the formation of silver by decomposition of silver chloride
(ii) sublimation of silver chloride
(iii decomposition of chlorine gas from silver chloride
(iv) oxidation of silver chloride
(a) (i) only
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (iv) only

Answer

Answer: a

---

10. MnO₂ + 4HCl → ₂ + 2H₂O + Cl₂
Identify the substance oxidized in the above . equation.
(a) MnCl₂
(b) HCl
(c) H₂O
(d) MnO₂

Answer/ Explanation

Answer: d
Explaination: Reason: In this reaction HCl is oxidised to Cl₂, whereas MnO₂ is reduced to MnCl₂.

---

11. A substance ‘X’ is used in white-washing and is obtained by heating limestone in the absence of air. Identify ‘X’.
(a) CaOCl₂
(b) Ca (OH)₂
(c) CaO
(d) CaCO₃

Answer/ Explanation

Answer:
Explaination:

---

12. When Ag is exposed to air it gets a black coating of
(a) AgNO₃
(b) Ag₂S
(c) Ag₂O
(d) Ag₂CO₃

Answer

Answer: b

---

13. Which of the following is an endothermic process?
(a) Dilution of sulphuric acid
(b) Sublimation of dry ice
(c) Condensation of water vapours
(d) Respiration in human beings

Answer

Answer: b

---

14. In the double displacement reaction between aqueous potassium iodide and aqueous lead nitrate, a yellow precipitate of lead iodide is formed. While performing the activity if lead nitrate is not available, which of the following can be used in place of lead nitrate?
(a) Lead sulphate (insoluble)
(&) Lead acetate
(c) Ammonium nitrate
(d) Potassium sulphate

Answer

Answer: b

---

15. What type of chemical reactions take place when electricity is passed through water?
(a) Displacement
(b) Combination
(c) Decomposition
(d) Double displacement

Answer/ Explanation

Answer: c
Explaination:

---

16. Select the oxidising agent for the following reaction:
H₂S + I₂ > 2HI + S
(a) I₂
(b) H₂S
(C) HI
(d) S

Answer

Answer: a

---

17. A substance added to food containing fats and oils is called:
(a) Oxidant
(b) Rancid
(c) Coolant
(d) Antioxidant

Answer

Answer: d

---

18. The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called:
(a) antioxidation
(b) reduction
(c) rancidity
(d) corrosion

Answer

Answer: c

---

19. Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is:
(a) 1 : 1
(b) 2:1
(c) 4:1
(d) 1:2

Answer

Answer: b

---

20. When S02 gas is passed through saturated solution of H2S, which of the following reaction occurs?
(a) SO₂ + 2H₂S → 2H20 + 3S
(b) SO₂ + 2H₂S → H20 + 3S
(c)SO₂ + H₂S → H₂O + S
(d) SO₂ + H₂O → SO₃ + H₂

Answer

Answer: a

---

21. Name the products formed when iron filings are heated with dilute hydrochloric acid
(a) Fe (III) chloride and water
(b) Fe (II) chloride and water
(c) Fe (II) chloride and hydrogen gas
(d) Fe (III) chloride and hydrogen gas

Answer/ Explanation

Answer: d
Explaination: Reason: 2Fe + 6HCl → 2FeCl₃ (Iron (III) chloride) + 3H₂

---

22. Pb + CuCl₂ → PbCl₂ + Cu
The above reaction is an example of:
(a) combination
(b) double displacement
(c) decomposition
(d) displacement

Answer

Answer: d

---

23. Which of the following gases can be used for storage (a) Carbon dioxide or Oxygen
(b) Nitrogen or Oxygen
(c) Carbon dioxide or Helium
(d) Helium or Nitrogen

Answer

Answer: d

---

24. A dilute ferrous sulphate solution was gradu¬ally added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disap¬pears. Which of the following is the correct explanation for the observation?
(a) KMnO₄ is an oxidising agent, it oxidises FeSO₄.
(b) FeSO₄ acts as an oxidising agent and oxidises KMNO₄.
(c) The colour disappears due to dilution; no reaction is involved.
(d) KMnO₄ is an unstable compound and de-composes in presence of FeSO₄. to a colourless compound.

Answer

Answer: a

---

25. In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature?
(a) 2H₂ (l) + O₂ (l) > 2H₂O(g)
(b) 2H₂ (g) + O₂ (l) > 2H₂O (l)
(c) 2H₂ (g) + O₂ (g) > 2H₂O (l)
(d) 2H₂ (g) +O₂ (g) > 2H₂O (g)

Answer

Answer: d

---

26. When green coloured ferrous sulphate crystals are heated, the colour of the crystal changes because
(a) it is decomposed to ferric oxide
(b) it loses water of crystallisation
(c) it forms SO₂
(d) it forms SO₃

Answer

Answer: b

---

27. 2HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + 2H₂O; is an example of
(i) displacement reaction
(ii) double displacement reaction
(iii) neutralisation reaction
(iv) combination reaction.
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)

Answer

Answer: b

---

28. Burning Magnesium ribbon is brought in the gas jar of carbon dioxide. Which of the following is correct ?
(i) It keeps on burning
(ii) It gets extinguished
(iii) Although CO₂ is non-supporter of combustion but burning magnesium breaks CO₂ into carbon and oxygen, oxygen helps in burning.
(iv) Carbon dioxide is supporter of combustion.
(a) (i) and (iv)
(b) (i) and (iii)
(c) (i) and (ii)
(d) (iii) and (iv)

Answer

Answer: b

---

29. What is observed when a solution of potassium iodide is added to silver nitrate solution ?
(a) No reaction takes place
(b) White precipitate of silver iodide is formed
(c) yellow precipitate of Agl is formed
(d) Agl is soluble in water.

Answer

Answer: c

---

30. Identify ‘x’, ‘y’ and ‘z’ in the following balanced reaction

(a) 2, 4, 2
(b) 2, 2, 4
(c) 2, 4, 4
(d) 4, 2, 2

Answer

Answer: b

---

31. Which of the following is precipitation as well as double displacement reaction?

Answer

Answer: d

---

32. Which of the following reactions will not take place ?
(a) Zn + CuSO₄ → ZnSO₃ + Cu
(b) 2KBr + Cl₂ → KCl + Br₂
(c) Zn + MgSO₄ → ZnSO₄ + Mg
(d) Mg + FeSO₄ → MgSO₄ + Fe

Answer

Answer: c

---

33. Which of the following involves combination of two elements ?
(a) N₂(g) + 3H₂(g) → 2NH₃(g)
(b) CaO(s) + CO₂(g) → CaCO₃(g)
(c) 2SO₂(g) + O₂(g) → 2SO₃f(g)
(d) NH₃(g) + HCl(g) → NH₄Cl(s)

Answer

Answer: a

---

34. In the reaction Hg₂Cl₂ + Cl₂ → 2HgCl₂ The reducing agent is
(a) Hg2Cl₂
(b) Cl₂
(c) HgCl₂
(d) Both Cl₂ and HgCl₂

Answer

Answer: a

---

35. Oxidation involves
(i) gain of electron
(ii) loss of electron
(iii) addition of oxygen or electronegative element
(iv) removal ofhydrogenorelectropositive element
(a) (i), (ii), (iii)
(b) (ii), (iii), (iv)
(c) (i), (iii), (iv)
(d) (i), (ii), (iv)

Answer

Answer: b

---

36. The formula of Ammonium phosphate is
(a) NH₄PO₄
(b) (NH₄)₂PO₄
(c) (NH₄)₃PO₄
(d) (NH₄)₃(PO₄)₂

Answer

Answer: c

---

37. Which of the following is a thermal decomposition reaction ?
(a) 2H₂O → 2H₂ + O₂
(b) 2AgCl → 2Ag + Cl₂
(c) ZnCO₃ → ZnO + CO₂
(d) H2(g) + Cl₂(g) → 2HCl(g)

Answer

Answer: c

---

38. The following reaction is an example of a
4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g)
(i) displacement reaction
(ii) combination reaction
(iii) redox reaction
(iv) neutralisation reaction [NCERT Exemplar Problems]
(a) (i) and (iv)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (iii) and (iv)

Answer

Answer: c

---

39. Which of the following statements about the given reaction are correct ?
3Fe(s) + 4H₂O(g) → Fe₃O₄(g) + 6H₂(g)
(i) Iron metal is getting oxidised
(ii) Water is getting reduced
(iii) Water is acting as reducing agent
(iv) Water is acting as an oxidising agent [NCERT Exemplar Problems]
(a) (i), (ii) and (iii)
(b) (iii) and (iv)
(c) (i), (ii) and (iv)
(d) (ii) and (iv)

Answer

Answer: c

---

40. Which of the following are exothermic processes?
(i) Reaction of water with quick lime
(ii) Dilution of an acid
(iii) Evaporation of water
(iv) Sublimation of camphor (crystals) [NCERT Exemplar Problems]
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (iii) and (iv)

Answer

Answer: a

---

41. Which among the following is (are) double displacement reactions ? [NCERT Exemplar Problems]
(i) Pb + CuCl₂ → PbCl₂ + Cu
(ii) Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl
(iii) C + O₂ → CO₂
(iv) CH₄ + 2O₂ → CO₂ + 2H₂O
(a) (i) and (iv)
(b) (ii) only
(c) (i) and (ii)
(d) (iii) and (iv)

Answer

Answer: b

---

42. Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of the reaction involved ? [NCERT Exemplar Problems]
(i) Displacement reaction
(ii) Precipitation reaction
(iii) Combination reaction
(iv) Double displacement reaction
(a) (i) only
(b) (ii) only
(c) (iv) only
(d) (ii) and (iv)

Answer

Answer: d

---

43. Electrolysis of water is a decomposition reaction. The molar ratio of hydrogen and oxygen gases liberated during electrolysis of water is [NCERT Exemplar Problems]
(a) 1 : 1
(b) 2 : 1
(c) 4 : 1
(d) 1 : 2

Answer

Answer: b

---

44. Which of the following is (are) an endothermic process(es) ? [NCERT Exemplar Problems]
(z) Dilution of sulphuric acid
(ii) Sublimation of dry ice
(iii) Condensation of water vapours
(iv) Evaporation of water
(a) (i) and (iii)
(b) (ii) only
(c) (iii) only
(d) (ii) and (iv)

Answer

Answer: d

---

45. Which of the following gases can be used for storage of fresh sample of an oil for a long time? [NCERT Exemplar Problems]
(a) Carbon dioxide or oxygen
(b) Nitrogen or oxygen
(c) Carbon dioxide or helium
(d) Helium or nitrogen

Answer

Answer: d

---

46. The following reaction is used for the preparation of oxygen gas in the laboratory

Which of the following statement(s) is (are) correct about the reaction ? [NCERT Exemplar Problems]
(a) It is a decomposition reaction and endothermic in nature
(b) It is a combination reaction
(c) It is a decomposition reaction and accompanied by release of heat
(d) It is a photochemical decomposition reaction and exothermic in nature

Answer

Answer: a

---

47. Which one of the following processes involve chemical reactions ? [NCERT Exemplar Problems]
(a) Storing of oxygen gas under pressure in a gas cylinder
(b) Liquefaction of air
(c) Keeping petrol in a china dish in the open
(d) Heating copper wire in presence of air at high temperature

Answer

Answer: d

---

48. In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature ? [NCERT Exemplar Problems]
(a) H₂(l) + O₂(l) → 2H₂O(g)
(b) H₂(g) + O₂(l) → 2H₂O(l)
(c) H₂(g) + O₂(g) → 2H₂O(l)
(d) H₂(g) + O₂(g) → m₂O(g)

Answer

Answer: c

---

49. The brown gas evolved on heating of copper nitrate is
(a) O₂
(b) NO₂
(c) N₂
(d) NO

Answer/Explanation

Answer: b
Explanation:

---

50. Zinc reacts with silver nitrate to form which compounds?
(a) Zn(NO₃)₂ + Ag
(b) ZnNO₃ + Ag
(c) AgNO₃ + Zn(NO₃)₂
(d) Ag + Zn(NO₃)₃

Answer/Explanation

Answer: a
Explanation:
(a) Zn + 2AgNO₃ → Zn(NO₃)₂ + 2Ag

---

51. MnO₂ + 4HCl → MnCl₂ + H₂O + Cl₂ The oxidising agent is
(a) MnO₂
(b) HCl
(c) MnCl₂
(d) Ag + Zn(NO₃)₃

Answer/Explanation

Answer: a
Explanation:
(a) MnO₂ is oxidising agent because it is removing hydrogen from HCl to form Cl₂.

---

52.

The colour of iodine is
(a) green
(b) purple
(c) brown
(d) pink

Answer/Explanation

Answer: b
Explanation:
(b) Iodine is purple in colour.

---

Direction (Q53 to Q57): In the following Questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.
(c) Assertion is true but the Reason is false.
(d) The statement of the Assertion is false but the Reason is true.
53. Assertion: AgBr is used on photographic and x-ray film.
Reason: AgBr is photosensitive and changes to Ag and bromine in presence of sunlight and undergoes decomposition reaction.

Answer/Explanation

Answer: a
Explanation:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

---

54. Assertion: Magnesium ribbon keeps on burning in atmosphere of nitrogen. Reason: Magnesium reacts with nitrogen to form magnesium nitrides and this reaction is combination reaction.

Answer/Explanation

Answer: a
Explanation:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

---

55. Assertion: Zinc reacts with sulphuric acid to form zinc sulphate and hydrogen gas and it is displacement reaction.
Reason: Zinc reacts with oxygen to form zinc oxide.

Answer/Explanation

Answer: b
Explanation:
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.

---

56. Assertion: MnO₂ + 4HCl → MnCl₂ + Cl₂ + 2H₂O is redox reaction.
Reason: MnO₂ oxides HCl to Cl₂ and gets reduced to MnCl₂.

Answer/Explanation

Answer: a
Explanation:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

---

57. Assertion: A lead nitrate on thermal decomposition gives lead oxide, brown coloured nitrogen dioxide and oxygen gas. Reason: Lead nitrate reacts with potassium iodide to form yellow ppt of lead iodide and the reaction is double displacement as well as precipitation reaction.

Answer/Explanation

Answer: b
Explanation:
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.

---

58. The colour of FeSO₄ crystal before ___________ heating is and after heating is ___________ .

Answer/Explanation

Answer:
Explanation: green, reddish brown

---

59. SO₂ + 2H₂S → 2H₂O + 3S; SO₂ is ___________ acting as agent.

Answer/Explanation

Answer:
Explanation: oxidising

---

60. The reaction Cu + xHNO₃ (cone.) → Cu(NO₃)₂ + yNO₂ + zH₂O The values of x, y and z are ___________ , ___________ and ___________ .

Answer/Explanation

Answer:
Explanation: 4, 2 and 2

---

61. A balanced chemical equation has equal masses of various elements in ___________ and ___________ .

Answer/Explanation

Answer:
Explanation: reactants, products

---

62.

is an example of ___________ reaction.

Answer/Explanation

Answer:
Explanation: decomposition

---

63. All combustion reactions are oxidation reactions. [True/False]

Answer/Explanation

Answer:
Explanation: True

---

64. Displacement reaction can be redox reaction also. [True/False]

Answer/Explanation

Answer:
Explanation: True

---

65. In H₂S + Cl₂ → 2HCl + S, Cl₂ is oxidising agent and H₂S is reducing agent. [True/False]

Answer/Explanation

Answer:
Explanation: True

---

66. CaO + 2HCl → CaCl₂ + H₂O is neutralisation reaction. [True/False]

Answer/Explanation

Answer:
Explanation: True

---

67. Chemical reactions are those processes where new substances with old properties are formed. [True/False]

Answer/Explanation

Answer:
Explanation: False

---

Direction: Match Column I with Column II.
68.

Answer/Explanation

Answer:
Explanation:
(i) (C)
(ii) (D)
(iii) (A)
(iv) (B)

---

69. State one basic difference between a physical change and a chemical change. [CBSE 2011]

Answer/Explanation

Answer:
Explanation:
In physical change, no new substance is formed whereas in a chemical change a new substance(s) is/are formed.

---

70. What is meant by a chemical reaction? [CBSE 2011]

Answer/Explanation

Answer:
Explanation:
The reaction representing a chemical change is called chemical reaction.

---

71. On what basis is a chemical equation balanced?

Answer/Explanation

Answer:
Explanation:
It is based on law of conservation of mass.

---

72. Balance the given chemical equation:
Al(s) + CuCl₂(ag) → AlCl(aq) + Cu(s)

Answer/Explanation

Answer:
Explanation:
2Al(s) + 3CuCl₂(aq) → 2AlCl₃(aq) + 3Cu(s)

---

73. Balance the given chemical equation:

Answer/Explanation

Answer:
Explanation:

---

74. Balance the given chemical equation:

Answer/Explanation

Answer:
Explanation:
3Fe(s) + 4H₂O(g) → Fe₃O₄(s) + 4H₂(g)

---

75. AgNO₃(aq) + NaCl(aq) → AgCl(g) ↓ + NaNO₃(aq)
FeS + H₂SO₄ → FeSO₄ + H₂S ↑
Consider the above mentioned two chemical equations with two different kinds of arrows ( ↑ and ↓) along with product. What do these two different arrows indicate? [CBSE 2011]

Answer/Explanation

Answer:
Explanation:
↑ shows the gas evolved whereas ↓ shows insoluble substance (precipitate) formed.

---

76. Hydrogen being a highly inflammable gas and oxygen being a supporter of combustion, yet water which is a compound made up of hydrogen and oxygen is used to extinguish fire. Why? [CBSE 2011]

Answer/Explanation

Answer:
Explanation:
It is because properties of compound (H₂O) are different from properties of its constituting elements i.e. H₂ and O₂.

---

77. What happens chemically when quicklime is added to water filled in a bucket?

Answer/Explanation

Answer:
Explanation:
Quicklime reacts with water to form slaked lime and produces lot of heat and hissing sound.

---

78. What change in colour is observed when white silver chloride is left exposed to sunlight? State the type of chemical reaction in this change.

Answer/Explanation

Answer:
Explanation:
Silver chloride becomes grey. It is a photochemical decomposition reaction.

---

79. How will you define a reducing agent?

Answer/Explanation

Answer:
Explanation:
Reducing agent is a substance which can lose electrons or which can add hydrogen or remove oxygen.

---

80. Potato chips manufacturers fill the packet of chips with nitrogen gas. Why? [DoE]

Answer/Explanation

Answer:
Explanation:
To provide an inert atmosphere to prevent chips from getting oxidised. N₂ does not allow chips to get spoiled by oxidation.

---

81. Why do gold and platinum not corrode in moist air?

Answer/Explanation

Answer:
Explanation:
They are least reactive and do not react with substances present in moist air.

---

82. Write two characteristics associated with rancid food.

Answer/Explanation

Answer:
Explanation:
Unpleasant smell and unpleasant taste.

---

83. How will you indicate the following effect in a chemical equation? A solution made in water.

Answer/Explanation

Answer:
Explanation:
A solution made in water is indicated by writing symbol (aq) with the symbol or formula of the substance concerned, aq stands for aqueous.

---

84. Give reason for the following:
The burning of natural gas is an exothermic reaction.

Answer/Explanation

Answer:
Explanation:
Burning of natural gas is an exothermic reaction because heat is produced in this reaction.

---

85. Give one example of a redox reaction which is also a combination reaction.

Answer/Explanation

Answer:
Explanation:
2Mg + O₂ → 2MgO

---

86. Balance the given chemical equation:
HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + H₂O

Answer/Explanation

Answer:
Explanation:
2HNO₃(aq) + Ca(OH)₂(aq) > Ca(N03)2(^) + 2H₂O(l)

---

Fill in the Blanks

1. The addition of oxygen to a substance is called …………. whereas removal of oxygen is called …………. .
2. The addition of hydrogen to a substance is called …………. whereas removal of hydrogen is called …………. .
3. Precipitation reactions produce insoluble …………. .
4. Reactions in which energy is given out are known as …………. .
5. Reaction in which an element displaces another element from its compound is called …………. .
6. Two antioxidants which are usually added to fat and oil containing foods to prevent rancidity, are …………., …………. .
7 …………. is the process in which metals are eaten up gradually by the action of air, moisture or a chemical on
their surface.
8. 2 FeSO₄ → Fe₂O₃ + SO₂ + ………….
9. Na₂SO₄ + BaCl₂ → …………. + 2NaCl
10. Complete the missing components/variables given as x and y in the following reactions:
(a) Pb (NO₃)₂ (aq) + 2KI (aq) → Pbl₂ (x) + 2KNO₃ (y)
(b) Cu (s) + 2AgNO₃ (aq) → Cu (NO₃)₂ (aq) + x (s)

Answers

1. oxidation, reduction
2. reduction, oxidation
3. salts
4. exothermic reactions
5. displacement reaction
6. BHA and BHT
7. Corrosion
8. SO3
9. BaSO4
10. (a) x → (s); y → (aq);
(b) x → 2Ag

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