📘 Chapter 2 – Exploring Substances: Acidic, Basic, Neutral

🔹 Part 4: Mixed Conceptual + Revision MCQs (Q76–Q100)

Q76. Which of these can be both natural and laboratory-made indicator?

A) Litmus
B) Phenolphthalein
C) Methyl orange
D) Turmeric

✅ Answer: A) Litmus

Explanation:
Litmus is extracted naturally from lichens but also prepared in labs.

Q77. Which solution is neutral in nature?

A) Vinegar
B) Distilled water
C) Lemon juice
D) Soap solution

✅ Answer: B) Distilled water

Q78. Which of the following is acidic in nature?

A) Baking soda
B) Soap
C) Tomato juice
D) Toothpaste

✅ Answer: C) Tomato juice

Q79. Which is a basic substance?

A) Vinegar
B) Lime water
C) Orange juice
D) Curd

✅ Answer: B) Lime water

Q80. Toothpaste is generally:

A) Acidic
B) Basic
C) Neutral
D) Salty

✅ Answer: B) Basic

Explanation:
Toothpaste is slightly basic to neutralise acids produced by bacteria in the mouth.

Q81. Which indicator shows different colours in acid and base?

A) Salt solution
B) Sugar solution
C) Litmus
D) Water

✅ Answer: C) Litmus

Q82. The pH of acidic solution is always:

A) Greater than 7
B) Equal to 7
C) Less than 7
D) Cannot be measured

✅ Answer: C) Less than 7

Q83. The pH of basic solution is always:

A) Greater than 7
B) Equal to 7
C) Less than 7
D) Exactly 7

✅ Answer: A) Greater than 7

Q84. Which of the following is used in fire extinguishers?

A) NaOH
B) HCl
C) Baking soda
D) Vinegar

✅ Answer: C) Baking soda

Explanation:
Baking soda releases CO₂ when heated, which helps to put out fires.

Q85. Which acid is present in apples?

A) Acetic acid
B) Citric acid
C) Tartaric acid
D) Malic acid

✅ Answer: D) Malic acid

Q86. Which acid is found in grapes?

A) Citric acid
B) Oxalic acid
C) Tartaric acid
D) Formic acid

✅ Answer: C) Tartaric acid

Q87. Which base is used in manufacturing soaps?

A) NaOH
B) HCl
C) H₂SO₄
D) NH₃

✅ Answer: A) NaOH

Q88. Which gas is released during neutralisation?

A) Hydrogen
B) Oxygen
C) Nitrogen
D) None

✅ Answer: D) None

Explanation:
Neutralisation produces only salt + water + heat, no gas.

Q89. Which indicator is preferred in titration of strong acid and strong base?

A) Phenolphthalein
B) Litmus
C) Onion
D) Turmeric

✅ Answer: A) Phenolphthalein

Q90. Which acid is present in tamarind?

A) Acetic acid
B) Tartaric acid
C) Citric acid
D) Lactic acid

✅ Answer: B) Tartaric acid

Q91. Which of these household substances is alkaline?

A) Lemon juice
B) Soap water
C) Vinegar
D) Curd

✅ Answer: B) Soap water

Q92. Which of these is not an acid-base indicator?

A) China rose
B) Turmeric
C) Onion
D) Sugar

✅ Answer: D) Sugar

Q93. The burning sensation caused by nettle leaves is due to:

A) Methanoic acid
B) Citric acid
C) Oxalic acid
D) Lactic acid

✅ Answer: A) Methanoic acid (Formic acid)

Q94. A base commonly used in washing powder is:

A) NaOH
B) Ca(OH)₂
C) Na₂CO₃
D) KOH

✅ Answer: C) Na₂CO₃ (Sodium carbonate)

Q95. Which of these is used in making cold drinks?

A) HCl
B) CO₂ (dissolved)
C) NaOH
D) Ammonia

✅ Answer: B) CO₂ (dissolved)

Q96. Which of these is an amphoteric substance (acts as both acid and base)?

A) NaOH
B) HCl
C) H₂O
D) NaCl

✅ Answer: C) H₂O (Water)

Q97. Which of these is a neutral salt?

A) NaCl
B) Na₂CO₃
C) NH₄Cl
D) CH₃COONa

✅ Answer: A) NaCl

Q98. Which one is used to neutralise acidic soil?

A) Vinegar
B) Lime (Ca(OH)₂)
C) Sugar
D) Salt

✅ Answer: B) Lime (Ca(OH)₂)

Q99. Which acid is used for cleaning rust in industries?

A) Hydrochloric acid
B) Acetic acid
C) Citric acid
D) Lactic acid

✅ Answer: A) Hydrochloric acid

Q100. Which of these shows neutralisation in daily life?

A) Baking soda to relieve ant sting
B) Vinegar for taste
C) Soap for washing
D) Water for drinking

✅ Answer: A) Baking soda to relieve ant sting

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