JEE Chemistry 2026 Question with Solution

Given: The cycloalkene (X) consumes one mole of bromine per mole of (X). The product (Y) has C : Br = $3:1$.

Find: The percentage of bromine in (Y).

For bromination of an alkene, one mole of $Br_2$ adds across one double bond. Therefore, the product contains two bromine atoms.

Since in product (Y), the ratio C : Br = $3:1$, and the actual number of bromine atoms in the product is $2$, the number of carbon atoms must be $6$.

So, the product is a dibromo cycloalkane with molecular formula:

Now calculate the molar mass of $C_6H_{10}Br_2$:

Mass of bromine in the product =

Therefore,

Nearest integer = $66$.

The solution contains an inconsistency: it lists Correct Answer: 67, but the worked chemistry and arithmetic give $66.12\%$, whose nearest integer is $66$. Following the provided the solution authority for the listed answer field, the recorded answer is 67, while the working indicates 66.