It is also prepared by treating aldehydes
and ketones with sodium borohydride (NaBH4) or lithium
aluminium hydride (LiAlH4) Aldehydes yield primary alcohols
whereas ketones give secondary alcohols (ii) By reduction of carboxylic acids and esters: Carboxylic acids
are reduced to primary alcohols in excellent yields by lithium
aluminium hydride, a strong reducing agent RCOOH
(i) LiAlH4
(ii) H O
2
RCH OH
2
However, LiAlH4 is an expensive reagent, and therefore,  used
for preparing special chemicals only