Q.In the Bouveault-Blanc reduction of >C=O group the reagent required is:

Bouveault-Blanc Reduction

The Bouveault–Blanc reduction is a classical dissolving-metal reduction that converts esters into primary alcohols using sodium metal in ethanol (or another alcohol). Developed by Louis Bouveault and Gustave Blanc in 1903, it was the standard laboratory method for reducing esters before catalytic hydrogenation and $LiAlH_4$ became common.

The overall transformation is:

The ester is reduced to a primary alcohol ($RCH_2OH$), while the alkoxy part ($OR'$) is released as a second alcohol ($R'OH$). Mechanistically, sodium supplies electrons to the carbonyl carbon, generating radical-anion (ketyl) intermediates; ethanol acts as the proton source. The reaction proceeds by successive single-electron transfers and protonations.

Worked example: Ethyl butanoate is reduced to butan-1-ol:

$CH_3CH_2CH_2COOC_2H_5 \xrightarrow{\text{Na / EtOH}} CH_3CH_2CH_2CH_2OH + C_2H_5OH$ …