SSC CGL 2024 Tier-I · 25 September 2024, Shift 3 · General Awareness · Question 9 of 100

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 10 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

Which acid is used as a souring agent added to vinegar, pickled vegetables, and sauces, and as a raw material for seasoning?

(a)Formic acid
(b)Citric acid
(c)Tartaric acid
(d)Acetic acid

Answer

Why

Correct — D. Vinegar simply is dilute acetic acid, so the souring agent the stem describes is acetic acid.

Its IUPAC name is ethanoic acid and its formula is CH₃COOH. Household vinegar is a 5-8% solution of it in water, which gives pickles and sauces their sharpness and preserves them by holding the pH low.

Pure acetic acid freezes at about 290 K, near room temperature in a cold climate, and is then called glacial acetic acid — option (d).

Why the others are wrong

(a)
Formic acid — Formic acid, methanoic acid HCOOH, is the simplest carboxylic acid and the sting in ant and nettle bites. It is not the acid of vinegar.
(b)
Citric acid — Citric acid is the acid of lemons, limes and oranges and is a common food acidulant, but vinegar's sourness does not come from it.
(c)
Tartaric acid — Tartaric acid occurs in tamarind and grapes and is the acid component of baking powder. It sours food, but it is not what vinegar contains.

Concept

Acetic acid is the second member of the carboxylic acid family, the group defined by the -COOH functional group.

It is a weak acid: in water it only partly ionises, which is why vinegar is safe on food while a strong acid of the same concentration would not be.

Industrially it is a feedstock as well as a flavour — vinyl acetate, acetic anhydride and ester solvents all start from it. In the kitchen its dilute form both sours and preserves, because most spoilage organisms cannot grow at the pH it produces.

Each option here is a real food acid, so the question is not 'which acid sours food' but the narrower 'which acid is vinegar'. Read the stem for the specific vehicle it names, and the family knowledge stops being enough on its own.

Key facts

Acetic acid's IUPAC name is ethanoic acid and its formula is CH₃COOH.
Vinegar is a 5-8% solution of acetic acid in water.
Pure acetic acid freezes at about 290 K and is then called glacial acetic acid.
Formic acid, HCOOH, is the simplest carboxylic acid.

Study next

Carboxylic acids: naming, formulae and everyday sourcesEsterification and saponification reactions of ethanoic acidCommon food acids matched to the fruit or product they come from

Common traps

Choosing citric acid because it is the food acid students meet first.
Swapping formic and acetic acid, which differ by one carbon: HCOOH against CH₃COOH.

SSC asks carboxylic acids by formula as well as by use. Butyric acid is asked from its chain formula at 09 Sep 2024, 16:00, GA Q.4, and the reverse direction, naming vitamin C as ascorbic acid, at 23 Sep 2024, 12:30, GA Q.23.

Related PYQs

No directly related past PYQ was found.