Class 10 Science MCQs Chapter 2 Acids Bases and Salts

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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


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.


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


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


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


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

Answer

Answer: d


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


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

Answer

Answer: a


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


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


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


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


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.


14. The apparatus given in the adjoining figure was set up to demonstrate electrical conductivity.
” alt=”” aria-hidden=”true” />MCQ Questions for Class 10 Science Acids Bases and Salts with Answers 1
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


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:
” alt=”” aria-hidden=”true” />MCQ Questions for Class 10 Science Acids Bases and Salts with Answers 2


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


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

Answer

Answer: a


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


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


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.


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


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.


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


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

Answer

Answer: a


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

Answer

Answer: d


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

Answer

Answer: d


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


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

Answer

Answer: a


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

Answer

Answer: a


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


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

Answer

Answer: a


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


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


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


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


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


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


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


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


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


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

Answer

Answer: b


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


43. In an attempt to demonstrate electrical conductivity through an electrolyte, the following apparatus was set up.
” alt=”” aria-hidden=”true” />MCQ Questions for Class 10 Science Acids Bases and Salts with Answers 1
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


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


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

Answer

Answer: d


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


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)
” alt=”” aria-hidden=”true” />MCQ Questions for Class 10 Science Acids Bases and Salts with Answers 2
(a) Red
(b) Yellow
(c) Yellowish green
(d) Blue

Answer

Answer: c


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


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


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


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


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.


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


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


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


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.


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.


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.


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.


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.


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

Answer/Explanation

Answer: a
Explanation: tartaric acid


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

Answer/Explanation

Answer: a
Explanation: methyl orange, phenolphthalein


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

Answer/Explanation

Answer: a
Explanation: hydrogen


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


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

Answer/Explanation

Answer: a
Explanation: alkali


66. The salts of carbonic acids are called _____________ .

Answer/Explanation

Answer: a
Explanation: carbonates


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

Answer/Explanation

Answer: a
Explanation: True


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

Answer/Explanation

Answer: a
Explanation: False


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


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

Answer/Explanation

Answer: a
Explanation: False


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


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

Answer/Explanation

Answer: a
Explanation: True


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

Column IColumn 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)


74.

Column IColumn II
A. Plaster of Paris(i) CaSO. 2H2O
B. Bleaching powder(ii) CaO
C. Washing soda(iii) CaSO. 1/2H2O
D. Gypsum(iv) Na2CO. 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)


75. What are indicators?

Answer/Explanation

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


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.


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.


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.


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

Answer/Explanation

Answer: a
Explanation: Universal indicator.


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

Answer/Explanation

Answer: a
Explanation: Hydrangea, Petunia, Geranium


81. What are phenolphthalein and methyl orange?

Answer/Explanation

Answer: a
Explanation: Synthetic indicators


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

Answer/Explanation

Answer: a
Explanation: Yellow.


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

Answer/Explanation

Answer: a
Explanation: Pink.


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

Answer/Explanation

Answer: a
Explanation: Reddish-brown.


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.


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

Answer/Explanation

Answer: a
Explanation: It changes to red.


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.


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.


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

Answer/Explanation

Answer: a
Explanation:
Beetroot extract.


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.


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.


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.


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

Answer/Explanation

Answer: a
Explanation:
Carbon dioxide gas is evolved.


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.


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.


96. Which planet contains yellowish clouds of sulphuric acid?

Answer/Explanation

Answer: a
Explanation: Venus.


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.


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.


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

Answer/Explanation

Answer: a
Explanation: CO2(g)


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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