Explain the method of obtaining alcohols from carboxylic acids and esters.

(N/A) From Carboxylic Acids: Carboxylic acids are reduced to primary alcohols in excellent yields by the use of a strong reducing agent,lithium aluminium hydride $(LiAlH_{4})$.
Since $LiAlH_{4}$ is an expensive reagent,it is used only for preparing special chemicals.
$(b)$ From Esters: On an industrial scale,carboxylic acids are first converted to esters,which are then reduced to alcohols by hydrogenation in the presence of a catalyst.
$RCOOH + R'OH$ $\xrightarrow{H^+} RCOOR'$ $\xrightarrow{H_2, \text{catalyst}} RCH_2OH + R'OH$