An unknown aldehyde A on reaction with alkali gives a `beta`- hydroxy aldehyd, which loses water to form an unsaturated aldehyde, But-2-enal. Another aldehyde 'B' disproporationation reaction in the presence of conc, alkali to form products C and D. C is an aryl alcohol wit the formula (`C_(2)H_(8))`
(1) Identify A and B.
(ii) Write the sequence of reactions involved.
(iii) Name the product, when B reacts with Zn amalgam and hydrochloric acid.

Explanation

To solve the problem step by step, we will identify the unknown aldehydes A and B, write the sequence of reactions involved, and name the product formed when B reacts with zinc amalgam and hydrochloric acid.

### Step 1: Identify Aldehyde A
The problem states that an unknown aldehyde A reacts with alkali to form a beta-hydroxy aldehyde, which then loses water to form but-2-enal. This indicates that A undergoes an aldol condensation reaction.

1. **Aldehyde A**: The simplest aldehyde that can undergo aldol condensation and yield but-2-enal is **acetaldehyde (CH3CHO)**.

### Step 2: Identify Aldehyde B
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