Question

Dodecane, a constituent of kerosene oil on heating to 973 K in the presence of nickel gives}

• A. pentane and hexane
• B. hexane and butane
• C. heptane and pentene
• D. heptene and pentane
• E. heptane and pentane

Hint:

Cracking of higher alkanes usually gives: \[ \text{smaller alkane} + \text{smaller alkene} \] Always check the molecular formula balance.

Answer 1

The Correct Option is C

Dodecane is: \[ C_{12}H_{26} \] On catalytic cracking, a long-chain alkane breaks into a smaller alkane and a smaller alkene. Check option (C): \[ \text{heptane} = C_7H_{16} \] \[ \text{pentene} = C_5H_{10} \] Adding them: \[ C_7H_{16} + C_5H_{10} = C_{12}H_{26} \] So this satisfies both carbon and hydrogen balance and matches the expected cracking pattern.
Hence, the correct answer is: \[ \boxed{(C)\ \text{heptane and pentene}} \]