Which of the following undergoes haloform reaction?
$ (i) \ CH_3CH_2COCH_2Cl $
$ (ii) \ C_6H_5COCH_3 $
$ (iii) \ C_6H_5COCHCl_2 $
$ (iv) \ CH_3CH_2COCCl_3 $

The reaction of $A$ to give $B$ and $C$ as shown in the reaction scheme is an example of:
$CH_2=CH_2$ $\xrightarrow[2. Zn/H_2O]{1. O_3} A$ $\xrightarrow{Conc. NaOH} B + C$
(Where $B$ is an alcohol and $C$ is a sodium salt of a carboxylic acid)

The major product $A$ is:

Arrange the following compounds in the decreasing order of their reactivity towards nucleophilic addition reactions:
$(I) \, HCHO \, (II) \, CH_3CHO \, (III) \, CH_3COCH_3$

The major product in the following reaction sequence is

The major product of the following reaction is :
$CH_3-CH_2-CHO \xrightarrow[\text{reflux}]{\text{excess } HCHO / \text{alkali}} ?$