Complete the following:
a. `2PhCHO+NH_(2)NH_(2)rarr`
b. Reduction of PhCHO with the following: i. LAH
ii. Clemmensen's reduction `(Zn(Hg)//conc. HCl)`
iii. Wolff-Kishner reduction `(NH_(2)NH_(2)+Glycol+overset(Θ)(OH))`

Explanation

Let's break down the question step by step.

### Step 1: Reaction of Benzaldehyde with Hydrazine
The first part of the question asks us to complete the reaction:
\[ 2 \text{PhCHO} + \text{NH}_2\text{NH}_2 \rightarrow \]

**Solution:**
When benzaldehyde (PhCHO) reacts with hydrazine (NH2NH2), it undergoes a nucleophilic addition reaction. The nitrogen from hydrazine attacks the carbonyl carbon of benzaldehyde, leading to the formation of a hydrazone. The reaction can be represented as follows:
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