Which one of the following is an organic acid?

Correct Answer: Option C — Acetic acid (CH₃COOH)

The question asks us to identify an organic acid from the given options.

What is an organic acid?

Organic acids are generally carbon-containing acids. Many common organic acids contain the –COOH (carboxyl) group.

Acetic acid (CH₃COOH) is an organic acid because it contains carbon and has the –COOH group. It is commonly found in vinegar and gives vinegar its characteristic sour taste.

Now, let's check the other options:

Option A: Hydrochloric acid (HCl) — It contains no carbon, so it is an inorganic acid.

Option B: Nitric acid (HNO₃) — It contains no carbon, so it is an inorganic acid.

Option C: Acetic acid (CH₃COOH) — It contains carbon and the –COOH group, making it an organic acid. It is found in vinegar.

Option D: Sulphuric acid (H₂SO₄) — It contains no carbon, so it is an inorganic acid.

Easy way to remember: Acetic acid → Vinegar → Organic acid.

Therefore, the correct answer is Option C: Acetic acid (CH₃COOH).