Show how the following alcohols are prepared by the reaction of a suitable Grignard reagent with methanal:
$(i)$ $CH_3-CH(CH_3)-CH_2OH$
$(ii)$ Cyclohexylmethanol .

(N/A) $(i)$ The reaction of isobutylmagnesium bromide with methanal $(HCHO)$:
$HCHO + CH_3-CH(CH_3)-CH_2-MgBr \to CH_3-CH(CH_3)-CH_2-CH_2-OMgBr$
$CH_3-CH(CH_3)-CH_2-CH_2-OMgBr \xrightarrow{H_2O/H^+} CH_3-CH(CH_3)-CH_2-CH_2-OH + Mg(OH)Br$
Note: The structure provided in the question $(i)$ is $CH_3-CH(CH_3)-CH_2OH$ (isobutanol),which is prepared from isopropylmagnesium bromide:
$HCHO + (CH_3)_2CH-MgBr \to (CH_3)_2CH-CH_2-OMgBr \xrightarrow{H_2O/H^+} (CH_3)_2CH-CH_2-OH + Mg(OH)Br$
$(ii)$ The reaction of cyclohexylmagnesium bromide with methanal $(HCHO)$:
$HCHO + C_6H_{11}-MgBr \to C_6H_{11}-CH_2-OMgBr$
$C_6H_{11}-CH_2-OMgBr \xrightarrow{H_2O/H^+} C_6H_{11}-CH_2-OH + Mg(OH)Br$