Formaldehyde undergoes Cannizzaro reaction because

(A)It has alpha-hydrogen atom.
(B) It does not have alpha-hydrogen atom.
(C) It does not undergo self-oxidation and reduction on heating with concentrated alkali.
(D) It undergoes self-oxidation and reduction on heating with concentrated alkali.

Choose the correct answer from the options given below:

The correct answer is (B) and (D) only.

Step-by-Step Explanation:

1. Understanding the Cannizzaro Reaction:
The Cannizzaro reaction is a chemical reaction that involves the base-induced disproportionation of non-enolizable aldehydes. In simpler terms, it is a self-oxidation and reduction reaction of aldehydes that lack an $\alpha$-hydrogen atom, when heated in the presence of a concentrated strong base (alkali).

2. Analyzing the Structure of Formaldehyde (HCHO):
The structural formula of formaldehyde is:
$H-\stackrel{||O}{C}-H$
An $\alpha$-hydrogen atom is a hydrogen atom attached to the carbon adjacent to the carbonyl carbon (the $\alpha$-carbon). In formaldehyde, there is no carbon adjacent to the carbonyl carbon. Therefore, formaldehyde does not possess any $\alpha$-hydrogen atom. Thus, statement (B) is correct.

3. Self-Oxidation and Reduction (Disproportionation):
Because formaldehyde lacks $\alpha$-hydrogens, it cannot undergo aldol condensation in basic medium. Instead, under the influence of a concentrated alkali (such as concentrated NaOH or KOH), one molecule of formaldehyde undergoes reduction to form methanol, while another molecule undergoes oxidation to form a formate salt (sodium formate). This combined process of simultaneous oxidation and reduction of the same reactant is known as self-oxidation and reduction (disproportionation). Thus, statement (D) is correct.

The overall reaction can be represented as:
$2HCHO+NaOH\to C{H}_{3}OH+HCOONa$
Since statements (B) and (D) correctly describe why formaldehyde undergoes the Cannizzaro reaction, the correct choice is (B) and (D) only.