JEE Chemistry 2023 Question with Solution

Given: A hydrocarbon $A$ undergoes complete combustion, requires $11$ equivalents of oxygen, and produces $4$ equivalents of water.

Find: The molecular formula of the hydrocarbon.

Let the molecular formula of the hydrocarbon be $C_xH_y$. The balanced combustion reaction is:

From the amount of water produced:

So,

Using the oxygen requirement:

Substitute $y = 8$:

Therefore, the hydrocarbon is $C_9H_8$. The correct option is A.

The solution marks option D, but the working clearly gives $C_9H_8$, which matches option A in the listed options.

Given: Hydrocarbon $C_xH_y$, oxygen required $= 11$ equivalents, water formed $= 4$ equivalents.

Find: Values of $x$ and $y$.

For complete combustion of a hydrocarbon:

Hence, the coefficient of water is $\frac{y}{2}$.

Since water produced is $4$ equivalents:

Now the oxygen coefficient in complete combustion is:

Given this is $11$, we get:

Thus the molecular formula is $C_9H_8$.