Class 10 Chemistry Worksheet on Chapter 2 Acids, Bases and Salts ... - Free Printable

Let's solve each question step by step:

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Q1. The property which is not shown by acids is:

- Options:
a.) They have a sour taste.
b.) They feel soapy.
c.) They turn litmus red.
d.) Their pH is less than 7.

Explanation:
- Acids have the following properties:
- They have a sour taste (e.g., vinegar).
- They turn blue litmus paper red.
- Their pH is less than 7 (acidic range).
- They do not feel soapy; that is a property of bases, not acids.

Answer:
b.) They feel soapy.

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Q2. A solution reacts with zinc granules to give a gas which burns with a pop sound. The solution contains:

- Options:
a.) Mg(OH)₂
b.) Na₂CO₃
c.) NaCl
d.) HCl

Explanation:
- When zinc reacts with an acid, it produces hydrogen gas (H₂). Hydrogen gas burns with a "pop" sound when ignited.
- The reaction is:
\[
\text{Zn} + 2\text{H}^+ \rightarrow \text{Zn}^{2+} + \text{H}_2 \uparrow
\]
- Among the options:
- Mg(OH)₂ is a base (magnesium hydroxide).
- Na₂CO₃ is a salt (sodium carbonate).
- NaCl is a salt (sodium chloride).
- HCl is an acid (hydrochloric acid).

Only HCl is an acid and will react with zinc to produce hydrogen gas.

Answer:
d.) HCl

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Q3. A solution turns red litmus blue. Its pH is likely to be:

- Options:
a.) 1
b.) 4
c.) 5
d.) 10

Explanation:
- Red litmus paper turns blue in basic solutions.
- Basic solutions have a pH greater than 7.
- Among the given options:
- pH = 1, 4, and 5 are all acidic (pH < 7).
- pH = 10 is basic (pH > 7).

Answer:
d.) 10

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Q4. Which of the following salts does not contain water of crystallisation?

- Options:
a.) Blue vitriol
b.) Baking soda
c.) Washing soda
d.) Gypsum

Explanation:
- Blue vitriol (CuSO₄·5H₂O): Contains 5 molecules of water of crystallization.
- Baking soda (NaHCO₃): Does not contain water of crystallization.
- Washing soda (Na₂CO₃·10H₂O): Contains 10 molecules of water of crystallization.
- Gypsum (CaSO₄·2H₂O): Contains 2 molecules of water of crystallization.

Answer:
b.) Baking soda

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Q5. Bases generate ___ ions in water.

- Options:
a.) H⁻
b.) H⁺
c.) OH⁻
d.) OH⁺

Explanation:
- Bases dissociate in water to produce hydroxide ions (OH⁻).
- For example:
- NaOH → Na⁺ + OH⁻
- KOH → K⁺ + OH⁻

Answer:
c.) OH⁻

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Q6. What is the role of tartaric acid in baking powder?

- Explanation:
- Baking powder is a leavening agent used in baking to make dough or batter rise.
- It typically consists of a weak acid (e.g., tartaric acid or cream of tartar) and a base (e.g., sodium bicarbonate).
- When baking powder is mixed with water and heated, the acid and base react to produce carbon dioxide gas (CO₂):
\[
\text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water} + \text{CO}_2
\]
- The carbon dioxide gas forms bubbles in the dough or batter, causing it to rise and become light and fluffy.

Answer:
Tartaric acid in baking powder reacts with the base (sodium bicarbonate) to produce carbon dioxide gas, which causes the dough or batter to rise.

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Final Answers:

1. b.) They feel soapy.
2. d.) HCl
3. d.) 10
4. b.) Baking soda
5. c.) OH⁻
6. Tartaric acid reacts with the base in baking powder to produce carbon dioxide gas, causing the dough or batter to rise.

Boxed Final Answer:
\[
\boxed{\text{b, d, d, b, c, Tartaric acid reacts with the base in baking powder to produce carbon dioxide gas, causing the dough or batter to rise.}}
\]