Question

Which of the following gives idoform test?

• A. $C{H}_{3}C{H}_{2}OH$
• B. $C_2{H}_{5}CHO$
• C. $(C{H}_{2}OH{)}_2$
• D. None of these

Answer 1

The correct option is A $C{H}_{3}C{H}_{2}OH$

Iodoform test is used to check the presence of carbonyl compounds with the structure $R-CO-C{H}_3$ or alcohols with the structure $R-CH\left(OH\right)-C{H}_3$ in a given unknown substance.

When Iodine and sodium hydroxide are added to a compound that contains either a methyl ketone or a secondary alcohol with a methyl group in the alpha position, a pale yellow precipitate of iodoform or triiodomethane is formed.
Here (a) compound shows positive iodoform test because $-OH$ is oxidised to carbonyl group by $NaOH+I_2$ which acts as a mild oxidising agent