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Chemistry Practice Questions

NCERT Class X Chapter 2: Acids, Bases and Salts

Created & Curated By S.K. Sinha

Section A: Questions
Q1.
An aqueous solution turns red litmus blue. Its pH is likely to be:
(A) 1
(B) 4
(C) 5
(D) 10
Q2.
The pH of lemon juice is approximately 2. This means it is:
(A) Strongly acidic
(B) Weakly acidic
(C) Neutral
(D) Basic
Q3.
Which of the following is used for whitewashing walls?
(A) Ca(OH)2
(B) CaCl2
(C) CaCO3
(D) CaSO4
Q4.
The salt that can be obtained by the reaction between Zn(OH)2 and HNO3 is:
(A) ZnSO4
(B) Zn(NO3)2
(C) ZnCl2
(D) ZnCO3
Q5.
Plaster of Paris is:
(A) CaSO4
(B) CaSO4ยท2H2O
(C) CaSO4ยทยฝH2O
(D) Ca(OH)2
Q6.
Which gas is produced when dilute hydrochloric acid is added to a reactive metal?
(A) Ammonia gas
(B) Carbon dioxide
(C) Hydrogen gas
(D) Nitrogen gas
Q7.
A solution reacts with crushed egg-shells to give a gas that turns lime water milky. The solution contains:
(A) NaCl
(B) HCl
(C) LiCl
(D) KCl
Q8.
What happens when a solution of an acid is mixed with a solution of a base in a test tube?
(A) The temperature of the solution increases
(B) The temperature of the solution decreases
(C) The temperature of the solution remains the same
(D) Salt formation takes place
Q9.
An organic acid found in vinegar is:
(A) Methanoic acid
(B) Ethanoic acid
(C) Propanoic acid
(D) Butanoic acid
Q10.
The water of crystallization in blue vitriol is:
(A) 2
(B) 5
(C) 7
(D) 10
Q11.
Sodium hydrogencarbonate is an ingredient of:
(A) Antacid
(B) Soap
(C) Baking powder
(D) Both (A) and (C)
Q12.
To protect tooth decay we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is:
(A) Acidic
(B) Neutral
(C) Basic
(D) Corrosive
Q13.
Which of the following salts does not contain water of crystallization?
(A) Blue vitriol
(B) Baking soda
(C) Washing soda
(D) Gypsum
Q14.
Calcium phosphate is present in tooth enamel. Its nature is:
(A) Basic
(B) Acidic
(C) Neutral
(D) Amphoteric
Q15.
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?
(A) Lemon juice
(B) Vinegar
(C) Common salt
(D) An antacid
Q16.
Which of the following gives the correct increasing order of acidic strength?
(A) Water < Acetic acid < Hydrochloric acid
(B) Water < Hydrochloric acid < Acetic acid
(C) Acetic acid < Water < Hydrochloric acid
(D) Hydrochloric acid < Water < Acetic acid
Q17.
If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?
(A) Wash the hand with saline water
(B) Wash the hand immediately with plenty of water and apply a paste of sodium hydrogencarbonate
(C) After washing with plenty of water apply solution of sodium hydroxide on the hand
(D) Neutralise the acid with a strong alkali
Q18.
Sodium carbonate is a basic salt because it is a salt of:
(A) Strong acid and strong base
(B) Weak acid and weak base
(C) Strong acid and weak base
(D) Weak acid and strong base
Q19.
Methyl orange is:
(A) A natural indicator
(B) An artificial indicator
(C) An olfactory indicator
(D) Not an indicator
Q20.
Which of the following is present in antacid?
(A) Sodium hydrogencarbonate
(B) Magnesium hydroxide
(C) Both (A) and (B)
(D) Sodium hydroxide
Q21.
Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) is added to test tube B. Amount and concentration taken for both the acids are same. In which test tube will the fizzing occur more vigorously and why?
(A) Test tube A because HCl is a stronger acid
(B) Test tube B because acetic acid is a stronger acid
(C) Both test tubes equally
(D) No fizzing will occur in either test tube
Q22.
Fresh milk has a pH of 6. When it changes into curd (yogurt), the pH value will:
(A) Become 7
(B) Become less than 6
(C) Become more than 7
(D) Remain unchanged
Q23.
Which of the following phenomenon will occur when a small amount of acid is added to water?
(A) Ionization
(B) Neutralization
(C) Dilution
(D) Salt formation
Q24.
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:
(A) Absorb the evolved gas
(B) Moisten the gas
(C) Absorb moisture from the gas
(D) Absorb Cl2 produced
Q25.
Which of the following salts will give an acidic solution when dissolved in water?
(A) CH3COONa
(B) NH4Cl
(C) NaCl
(D) KNO3
Section B: Answers
Question Answer
Q1 (D)
Q2 (A)
Q3 (A)
Q4 (B)
Q5 (C)
Q6 (C)
Q7 (B)
Q8 (A)
Q9 (B)
Q10 (B)
Q11 (D)
Q12 (C)
Q13 (B)
Q14 (A)
Q15 (D)
Q16 (A)
Q17 (B)
Q18 (D)
Q19 (B)
Q20 (C)
Q21 (A)
Q22 (B)
Q23 (C)
Q24 (C)
Q25 (B)
Section C: Solutions
Q1.
Basic solution turns red litmus blue; pH > 7.
Q2.
pH = 2 indicates strong acidity (pH < 3).
Q3.
Calcium hydroxide (slaked lime) is used for whitewashing.
Q4.
Base + Acid โ†’ Salt + Water; Zn(OH)2 + 2HNO3 โ†’ Zn(NO3)2 + 2H2O
Q5.
Plaster of Paris has half molecule of water of crystallization.
Q6.
Metal + Acid โ†’ Salt + Hydrogen gas.
Q7.
HCl reacts with CaCO3 to produce CO2 that turns lime water milky.
Q8.
Neutralization is exothermic; temperature increases.
Q9.
Vinegar contains ethanoic acid (CH3COOH).
Q10.
Blue vitriol is CuSO4ยท5H2O.
Q11.
NaHCO3 is used in both antacids and baking powder.
Q12.
Toothpaste is basic to neutralize acid produced by bacteria.
Q13.
Baking soda (NaHCO3) has no water of crystallization.
Q14.
Calcium phosphate is a salt of weak acid and strong base, hence basic.
Q15.
Yellowish-orange indicates acidic soil; antacid will neutralize it.
Q16.
Water < Acetic acid < HCl (increasing acid strength).
Q17.
Wash immediately with water, then apply NaHCO3 paste to neutralize.
Q18.
Na2CO3 is salt of strong base (NaOH) and weak acid (H2CO3).
Q19.
Methyl orange is a synthetic/artificial indicator.
Q20.
Both NaHCO3 and Mg(OH)2 neutralize stomach acid.
Q21.
HCl is stronger acid than acetic acid, so more vigorous reaction.
Q22.
Lactic acid formation makes curd more acidic; pH decreases.
Q23.
Adding acid to water dilutes the acid concentration.
Q24.
CaCl2 is a drying agent that absorbs moisture.
Q25.
NH4Cl is salt of strong acid and weak base, giving acidic solution.

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