The compound shown is treated with excess Br2 in CCl4 in the dark, which adds to every non-aromatic C=C. What is the degree of unsaturation of the product?

JEE Main levelSingle correct optionDifficulty 2 of 3si233

The compound shown is treated with excess $Br X_{2}$ in $CCl X_{4}$ in the dark, which adds to every non-aromatic C=C. What is the degree of unsaturation of the product?

The compound shown is 1-phenylbuta-1,3-diene,

C X_{10} H X_{10}

, DBE 6. Two C=C bonds add 2 mol

Br X_{2}

, giving

C X_{10} H X_{10} Br X_{4}

with DBE

= (22 - 14) /2 = 4

(the benzene ring is untouched). So the answer is 4.