Aldehydes and ketones, having atleast one methyl group linked to the carbonyl carbon atom (methyl ketones), are oxidized by sodium hypohalite to sodium salts of corresponding carboxylic acids having one carbon atom less than that of carbonyl compound is converted to haloform. This oxidation does not affect a carbon-carbon double bond, if present in a molecule.

Arrange in decreasing order of nucleophilic addition:

(A)    \(CH_3CHO\)

(B)    \(C_2H_5COCH_3\)

(C)    \(CH_3COCH_3\)

(D)   \(HCHO\)

Choose the correct answer from the options given below:

(D) > (A) > (C) > (B)

The nucleophilic addition reaction typically occurs in the carbonyl group in aldehydes and ketones. In these reactions, nucleophiles attack the partially positive carbon atom of the carbonyl group, forming a new bond.
The nucleophilic addition reactivity generally follows the order:
1. Aldehydes are more reactive than ketones because they have a less bulky R group attached to the carbonyl group, making the carbonyl carbon more accessible to nucleophilic attack.
2. Among aldehydes, formaldehyde (HCHO) is the most reactive because it has the least steric hindrance around the carbonyl carbon.
3. Among ketones, the reactivity depends on the nature of the R groups. Ketones with smaller alkyl groups are generally more reactive than those with bulkier alkyl groups.
Now, let's analyze the given compounds:
(A) \(CH_3CHO\) - This is formaldehyde, an aldehyde with a small methyl group.
(B) \(C_2H_5COCH_3\) - This is acetone, a ketone with two methyl groups.
(C) \(CH_3COCH_3\) - This is also acetone.
(D) \(HCHO\) - This is formaldehyde.
Based on the principles mentioned above, we can arrange these compounds in decreasing order of nucleophilic addition as follows: (D) > (A) > (C) > (B)
So, the correct answer is (1) (D) > (A) > (C) > (B).