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Problem: Solving the Multiple-Choice Questions on Acids, Bases, and Salts

The provided worksheet contains multiple-choice questions related to acids, bases, and salts. Below is a detailed explanation of each question and its solution.

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#### Question 1:
Plants in my garden were not bearing flowers and appeared dull despite all the care I took. I treated the soil solution with litmus and it turned red. What should I add to the soil to ensure better growth of plants?

- (A) Manure
- (B) Slaked lime
- (C) Lemon juice
- (D) Soap solution

Explanation:
- When litmus paper turns red upon contact with a solution, it indicates that the solution is acidic.
- Plants generally grow best in slightly acidic to neutral soil (pH around 6–7). However, if the soil is too acidic (low pH), it can inhibit nutrient uptake and plant growth.
- To neutralize overly acidic soil, a base needs to be added. Slaked lime (calcium hydroxide) is a strong base commonly used to raise the pH of acidic soil.
- Manure is organic matter that adds nutrients but does not significantly alter pH.
- Lemon juice is acidic and would make the soil even more acidic.
- Soap solution is mildly basic but not typically used for soil amendment.

Correct Answer: (B) Slaked lime

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#### Question 2:
An example of an acid derived from a mineral is:

- (A) Citric Acid
- (B) Nitric Acid
- (C) Acetic Acid
- (D) Tartaric Acid

Explanation:
- Citric Acid is found in citrus fruits and is not derived from minerals.
- Nitric Acid is a strong mineral acid derived from the mineral nitrate (found in natural deposits like sodium nitrate).
- Acetic Acid is found in vinegar and is produced by fermentation, not from minerals.
- Tartaric Acid is found in grapes and other fruits and is not derived from minerals.

Correct Answer: (B) Nitric Acid

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#### Question 3:
An acid present in aerated drinks is:

- (A) Lactic acid
- (B) Maleic acid
- (C) Carbonic acid
- (D) Citric acid

Explanation:
- Lactic acid is found in sour milk and fermented foods, not in aerated drinks.
- Maleic acid is not commonly found in aerated drinks.
- Carbonic acid is formed when carbon dioxide dissolves in water, which is the primary component of aerated drinks like soda and sparkling water.
- Citric acid is found in citrus fruits and is sometimes added to drinks for flavor, but it is not the primary acid in aerated drinks.

Correct Answer: (C) Carbonic acid

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#### Question 4:
For burning sensation in the stomach which type of medicine is used?

- (A) Antibiotic
- (B) Analgesic
- (C) Antacid
- (D) Antiseptic

Explanation:
- Antibiotics are used to treat bacterial infections, not stomach burns.
- Analgesics are painkillers and do not address stomach acidity.
- Antacids are medicines that neutralize excess stomach acid, relieving symptoms like heartburn or burning sensations.
- Antiseptics are used to kill germs on the skin or surfaces, not for internal use.

Correct Answer: (C) Antacid

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#### Question 5:
Blood is:

- (A) Acidic
- (B) Basic
- (C) Neutral

Explanation:
- Blood has a slightly alkaline pH, typically between 7.35 and 7.45. This slight alkalinity is crucial for maintaining homeostasis in the body.
- Acidic solutions have a pH below 7.
- Neutral solutions have a pH of exactly 7.
- Basic solutions have a pH above 7, which matches the pH range of blood.

Correct Answer: (B) Basic

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#### Question 6:
Which of these if heated in an aluminum pan would corrode the pan most?

- (A) Water
- (B) Eggs
- (C) Tomato juice
- (D) Milk

Explanation:
- Water is neutral (pH ≈ 7) and will not corrode aluminum.
- Eggs are slightly basic (pH ≈ 8–9) and will not corrode aluminum.
- Tomato juice is acidic (pH ≈ 4) and contains citric and malic acids, which can react with aluminum to form aluminum salts, causing corrosion.
- Milk is slightly acidic (pH ≈ 6.5–6.8) but is not as corrosive as tomato juice.

Correct Answer: (C) Tomato juice

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#### Question 7:
If lemon juice is mixed with marble chips, it will dissolve some of the marble chips.

- (A) True
- (B) False

Explanation:
- Lemon juice is acidic (contains citric acid) and reacts with calcium carbonate (the main component of marble chips) to form calcium citrate, water, and carbon dioxide:
\[
\text{CaCO}_3 + 2\text{H}^+ \rightarrow \text{Ca}^{2+} + \text{H}_2\text{O} + \text{CO}_2
\]
- This reaction causes the marble chips to dissolve partially.

Correct Answer: (A) True

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#### Question 8:
Sulphuric acid is used in car batteries.

- (A) True
- (B) False

Explanation:
- Sulphuric acid (\(\text{H}_2\text{SO}_4\)) is a key component of lead-acid batteries used in cars. It acts as the electrolyte, facilitating the chemical reactions that produce electricity.

Correct Answer: (A) True

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Final Answers:

1. (B) Slaked lime
2. (B) Nitric Acid
3. (C) Carbonic acid
4. (C) Antacid
5. (B) Basic
6. (C) Tomato juice
7. (A) True
8. (A) True

Boxed Final Answer:
\[
\boxed{(B), (B), (C), (C), (B), (C), (A), (A)}
\]