Acids

Which acid is found in lemon juice?
a) Acetic acid
b) Citric acid
c) Tartaric acid
d) Oxalic acid
✅ b) Citric acid
Explanation: Citric acid occurs naturally in citrus fruits like lemons and oranges.
(BPSC 66th Prelims)
Which of the following is a mineral acid?
a) Lactic acid
b) Sulfuric acid
c) Tartaric acid
d) Citric acid
✅ b) Sulfuric acid
Explanation: Sulfuric acid is an industrially prepared mineral acid.
(BPSC Teacher 2023)
Which acid is used in car batteries?
a) Nitric acid
b) Hydrochloric acid
c) Sulfuric acid
d) Acetic acid
✅ c) Sulfuric acid
Explanation: Sulfuric acid acts as an electrolyte in lead-acid batteries.
(CDPO 2017)
Which acid is responsible for the sour taste in vinegar?
a) Oxalic acid
b) Acetic acid
c) Citric acid
d) Hydrochloric acid
✅ b) Acetic acid
Explanation: Acetic acid (CH₃COOH) gives vinegar its sour flavor.
(BPSC 60th Prelims)
Hydrochloric acid is produced in:
a) Small intestine
b) Mouth
c) Pancreas
d) Stomach
✅ d) Stomach
Explanation: Gastric glands secrete HCl to aid digestion.
(BPSC Teacher 2023)
Which of these acids is found in tomato?
a) Acetic
b) Citric
c) Oxalic
d) Formic
✅ c) Oxalic
Explanation: Tomato contains oxalic acid, which also contributes to kidney stones.
(BPSC 67th Prelims)
Which acid is responsible for the sting of ants?
a) Lactic acid
b) Formic acid
c) Citric acid
d) Oxalic acid
✅ b) Formic acid
Explanation: Formic acid is secreted by ants and red insects.
(BPSC 65th Prelims)
Which acid is used in the manufacture of fertilizers?
a) Hydrochloric acid
b) Acetic acid
c) Nitric acid
d) Tartaric acid
✅ c) Nitric acid
Explanation: Nitric acid is used to make ammonium nitrate and urea.
(BPSC Prelims PYQ)
The chemical formula of sulfuric acid is:
a) HNO₃
b) H₂SO₄
c) HCl
d) CH₃COOH
✅ b) H₂SO₄
Explanation: H₂SO₄ is a strong diprotic acid.
(CDPO 2015)
Which acid is used for removing rust?
a) Hydrochloric acid
b) Sulfuric acid
c) Oxalic acid
d) Acetic acid
✅ c) Oxalic acid
Explanation: Oxalic acid is often used as a cleaning agent for iron rust.
(BPSC Assistant 2019)

NCERT-Based MCQs (Q11–30)

Acids turn blue litmus:
a) Red
b) Green
c) Yellow
d) No change
✅ a) Red
Explanation: Acids turn blue litmus paper red — a standard test.
Which of the following is a weak acid?
a) HCl
b) CH₃COOH
c) H₂SO₄
d) HNO₃
✅ b) CH₃COOH
Explanation: Acetic acid is a weak organic acid.
Which acid is found in milk?
a) Citric acid
b) Lactic acid
c) Tartaric acid
d) Malic acid
✅ b) Lactic acid
Explanation: Lactic acid forms in sour milk and curd.
Acid + Base → ?
a) Water + Acid
b) Salt + Water
c) Salt + Base
d) Only salt
✅ b) Salt + Water
Explanation: This is a neutralization reaction.
Which of these is not acidic in nature?
a) Lemon juice
b) Baking soda solution
c) Tamarind
d) Curd
✅ b) Baking soda solution
Explanation: Baking soda is alkaline, not acidic.
Which acid is found in grapes?
a) Acetic
b) Tartaric
c) Citric
d) Formic
✅ b) Tartaric
Explanation: Grapes contain tartaric acid.
Which acid is used in pickling?
a) Hydrochloric acid
b) Acetic acid
c) Sulfuric acid
d) Formic acid
✅ b) Acetic acid
Explanation: Vinegar (acetic acid) preserves food and inhibits bacterial growth.
Organic acids are usually:
a) Strong acids
b) Weak acids
c) Neutral
d) Salts
✅ b) Weak acids
Explanation: They only partially ionize in water.
Which acid is produced by muscle cells during strenuous exercise?
a) Lactic acid
b) Acetic acid
c) Citric acid
d) Malic acid
✅ a) Lactic acid
Explanation: Anaerobic respiration in muscles produces lactic acid.
The pH of a strong acid is:
a) Above 7
b) 7
c) Below 7
d) Exactly 14
✅ c) Below 7
Explanation: Strong acids have a pH between 0 and 3.
Which acid is present in apples?
a) Oxalic
b) Lactic
c) Malic
d) Citric
✅ c) Malic
Explanation: Malic acid contributes to the tartness of apples.
The term "acid" is derived from a Latin word meaning:
a) Salty
b) Bitter
c) Sour
d) Alkaline
✅ c) Sour
Explanation: "Acidus" in Latin means sour.
Which acid is commonly used in car radiators?
a) Nitric acid
b) Citric acid
c) Acetic acid
d) None
✅ d) None
Explanation: Radiators typically use antifreeze, not acids.
Which of the following is a dibasic acid?
a) HCl
b) HNO₃
c) H₂SO₄
d) H₃PO₄
✅ c) H₂SO₄
Explanation: It can donate two H⁺ ions.
pH paper turns _____ in acid.
a) Red
b) Green
c) Blue
d) Purple
✅ a) Red
Explanation: Acidic solutions cause red coloration on pH paper.
Acid present in tamarind is:
a) Acetic acid
b) Tartaric acid
c) Malic acid
d) Formic acid
✅ b) Tartaric acid
Explanation: Tamarind is rich in tartaric acid.
Acids are:
a) Electron donors
b) Proton donors
c) Neutrons donors
d) Electron acceptors
✅ b) Proton donors
Explanation: According to Brønsted–Lowry theory.
Which of the following is a tribasic acid?
a) HNO₃
b) H₂SO₄
c) HCl
d) H₃PO₄
✅ d) H₃PO₄
Explanation: Phosphoric acid has 3 replaceable H⁺ ions.
Which of the following acids is added to soft drinks?
a) Sulfuric acid
b) Nitric acid
c) Carbonic acid
d) Citric acid
✅ c) Carbonic acid
Explanation: CO₂ dissolved in water forms carbonic acid.
Which acid is found in tea?
a) Oxalic acid
b) Lactic acid
c) Tartaric acid
d) None
✅ a) Oxalic acid
Explanation: Oxalic acid is naturally present in tea leaves.

Acids – MCQs 31 to 50 with Explanations (BPSC Prelims)

Predicted and Conceptual MCQs

Which acid is present in sour milk?
a) Citric acid
b) Acetic acid
c) Lactic acid
d) Tartaric acid
✅ c) Lactic acid
Explanation: Lactic acid is formed by bacterial fermentation in curdled milk.
Which of the following is used as a coagulant in rubber industry?
a) Acetic acid
b) Hydrochloric acid
c) Sulfuric acid
d) Oxalic acid
✅ a) Acetic acid
Explanation: Acetic acid helps in coagulating latex to produce rubber.
Which of these acids is commonly used in cleaning toilets?
a) Hydrochloric acid
b) Nitric acid
c) Formic acid
d) Acetic acid
✅ a) Hydrochloric acid
Explanation: HCl is a common ingredient in toilet cleaning agents.
Which acid is found in sour cream?
a) Malic acid
b) Citric acid
c) Lactic acid
d) Oxalic acid
✅ c) Lactic acid
Explanation: Sour cream develops lactic acid during fermentation.
Which of these acids is known to be dibasic?
a) Nitric acid
b) Acetic acid
c) Sulfuric acid
d) Hydrochloric acid
✅ c) Sulfuric acid
Explanation: Dibasic acids release 2 H⁺ ions per molecule.
Which of the following is not an organic acid?
a) Acetic acid
b) Tartaric acid
c) Citric acid
d) Sulfuric acid
✅ d) Sulfuric acid
Explanation: Sulfuric acid is a mineral acid made industrially.
Which acid is used in the manufacture of explosives?
a) Hydrochloric acid
b) Acetic acid
c) Nitric acid
d) Tartaric acid
✅ c) Nitric acid
Explanation: Nitric acid is a key ingredient in TNT and other explosives.
Which acid helps digest proteins in the stomach?
a) Nitric acid
b) Hydrochloric acid
c) Lactic acid
d) Acetic acid
✅ b) Hydrochloric acid
Explanation: HCl activates pepsin enzyme for protein breakdown.
Which of the following acids is used in ink and dyes?
a) Oxalic acid
b) Formic acid
c) Tannic acid
d) Acetic acid
✅ c) Tannic acid
Explanation: Tannic acid is used in making inks and dyeing leather.
Acid found in sour apple is:
a) Oxalic acid
b) Citric acid
c) Malic acid
d) Tartaric acid
✅ c) Malic acid
Explanation: Green apples contain malic acid contributing to their sourness.
Which acid occurs in rhubarb leaves?
a) Oxalic acid
b) Citric acid
c) Tartaric acid
d) Lactic acid
✅ a) Oxalic acid
Explanation: Rhubarb contains high oxalic acid, which is mildly toxic in excess.
The acid used in manufacture of rayon is:
a) Sulfuric acid
b) Acetic acid
c) Hydrochloric acid
d) Formic acid
✅ a) Sulfuric acid
Explanation: It helps convert cellulose into viscose rayon.
Which acid is present in unripe mangoes?
a) Tartaric acid
b) Lactic acid
c) Malic acid
d) Citric acid
✅ a) Tartaric acid
Explanation: Gives raw mangoes their sour flavor.
What is the acid found in grapes and bananas?
a) Lactic acid
b) Tartaric acid
c) Citric acid
d) Malic acid
✅ b) Tartaric acid
Explanation: Grapes and bananas are rich in tartaric acid.
Which acid is found in spinach and can contribute to kidney stones?
a) Citric acid
b) Oxalic acid
c) Acetic acid
d) Lactic acid
✅ b) Oxalic acid
Explanation: Excess oxalate forms calcium oxalate stones in kidneys.
Which acid is used to etch glass?
a) Sulfuric acid
b) Nitric acid
c) Hydrofluoric acid
d) Acetic acid
✅ c) Hydrofluoric acid
Explanation: HF reacts with silicon dioxide in glass.
Acid commonly used in food preservatives is:
a) Sulfuric acid
b) Acetic acid
c) Benzoic acid
d) Nitric acid
✅ c) Benzoic acid
Explanation: Sodium benzoate and benzoic acid prevent microbial growth in food.
What kind of acid is used to clean marble surfaces?
a) Hydrochloric acid
b) Nitric acid
c) Oxalic acid
d) Acetic acid
✅ c) Oxalic acid
Explanation: Gently removes iron rust and stains from marble.
Which acid can burn skin and cause severe corrosion?
a) Acetic acid
b) Citric acid
c) Sulfuric acid
d) Malic acid
✅ c) Sulfuric acid
Explanation: Highly corrosive, it dehydrates and chars organic matter.
The chemical name of Vitamin C is:
a) Folic acid
b) Tartaric acid
c) Ascorbic acid
d) Lactic acid
✅ c) Ascorbic acid
Explanation: Vitamin C is a weak organic acid essential for immunity.