Question

When isobutene is monochlorinated in the presence of ultraviolet light, the product obtained in higher yield is

• A. n-butyl chloride
• B. isobutylchloride
• C. see-butyl chloride
• D. tert-butyl chloride

Answer 1

Answer: (B)

$\frac{\%\text{ of isobutyl chloride }}{\%\text{ of }\text{ tert-butyl chloride }}=\frac{\text{ no. of primary }H}{\text{ no. of tertiary }H}\times \frac{\text{ reactivity of }{1}^{\circ }H}{\text{ reactivity of }{3}^{\circ }H}=\frac{9}{1}\times \frac{1}{5}=\frac{9}{5}$
$\%$ of isobutyl chloride $=\frac{9}{9+5}\times 100=74.3\%$
$\%$ of tert-butyl chloride $=\frac{9}{14}\times 100=25.7\%$