Question

80. Which of the following is not a hydroxy acid?
(1) Lactic acid
(2) Pyruvic acid
(3) Tartaric acid
(4) Citric acid​

Answer 1

Answer:

2nd pyruvic acid

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Answer 2

(2) Pyruvic acid

1. The rest of the options are hydroxy acids while Pyruvic acid is a carboxylic acid.
2. Hydroxy acids have at least two carboxylic groups while Pyruvic acid only has one.
3. Formulas of the acids:

• Lactic acid - $C_{3} H_{6} O_{3}$
• Pyruvic acid - $C_{3} H_{4} O_{3}$
• Tartaric acid - $C_{4} H_{6} O_{6}$
• Citric acid - $C_{6} H_{8} O_{7}$

    Hence, Pyruvic acid is NOT a hydroxy acid.