Question

Following compounds are given
(i) $C{H}_{3}C{H}_{2}OH$ (ii) $C{H}_{3}COC{H}_3$
(iii) $C{H}_3-\underset{\underset{C{H}_3}{|}}{C}HOH$ (iv) $C{H}_{3}OH$
Which of the above compound(s) on being warmed with iodine solution and $NaOH$, will give iodoform?

• A. $\left(i\right),\left(iii\right)$ and $\left(iv\right)$
• B. Only $\left(ii\right)$
• C. $\left(i\right),\left(ii\right)$ and $\left(iii\right)$
• D. $\left(i\right)$ and $\left(ii\right)$

Answer 1

Answer: (C)

$\left(i\right),\left(ii\right)$ and $\left(iii\right)$

Compounds having either $C{H}_3\stackrel{\stackrel{O}{\parallel }}{C}-$ group or $C{H}_{3}CH\left(OH\right)$ - group, give iodoform when warmed with $I_2$ and $NaOH$.
Thus, compounds
$C{H}_3\underset{\underset{H}{|}}{C}HOH,C{H}_3-\stackrel{\stackrel{O}{\parallel }}{C}-C{H}_3,C{H}_3-\underset{\underset{C{H}_3}{|}}{C}HOH$
Given iodoform when heated with $I_2$ and $NaOH$. (Note: $NaOI$ oxidises $C{H}_{3}C{H}_{2}OH$ to $C{H}_{3}CHO$, and gives positive iodoform test.)