Explanation

(a)
Iodoform test is done to detect presence of $CH_{3}CO\$group in organic compounds.
Fehling solution identifies aldehydes.
Tollen’s reagent identifies aldehydes.
Schiff’s reagent identifies aldehydes.
O
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \parallel$
Methyl ketone is $CH_{3} - C - R.$
O
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \parallel \ \ \ \ \ \ \ \$
$\because$ It has $CH_{3} - C$ group. It is tested by using iodoform test.
The compound having $CH_{3}CO$ group give yellow ppt. on reaction with $I_{2}$ and aqueous alkali.