The compound 3-cyano-4-oxohex-2-enoic acid contains a carboxylic acid, a C=C, a nitrile and a ketone in one open chain. Its molecular formula is C7H7NO3. Calculate its degree of unsaturation (number of rings plus pi bonds equivalents), as an integer.

JEE Main levelNumerical answerDifficulty 2 of 3nm059

The compound 3-cyano-4-oxohex-2-enoic acid contains a carboxylic acid, a C=C, a nitrile and a ketone in one open chain. Its molecular formula is $C X_{7} H X_{7} NO X_{3}$ . Calculate its degree of unsaturation (number of rings plus pi bonds equivalents), as an integer.

Numerical answer type, tolerance 0.5.

Degree of unsaturation =

(2 C + 2 + N - H) /2 = (14 + 2 + 1 - 7) /2 = 5

. This matches the structure: one C=O of the acid, one C=C, two for the C

\equiv

N and one ketone C=O. The answer is 5.