The reagent $X$ in the reaction sequence: $(CH_3)_3C-CH=CH_2$ $\xrightarrow[THF]{X} Y$ $\xrightarrow[NaOH]{NaBH_4} (CH_3)_3C-CH(OH)-CH_3$ is:

Show how will you synthesize:
$(i)$ $1-$phenylethanol from a suitable alkene.
$(ii)$ cyclohexylmethanol using an alkyl halide by an $S_{N}2$ reaction.
$(iii)$ pentan$-1-$ol using a suitable alkyl halide?

Ethanol can be prepared more easily by which reaction?
$(i) \ CH_3CH_2Br + H_2O \longrightarrow CH_3CH_2OH + HBr$
$(ii) \ CH_3CH_2Br + Ag_2O \text{ (moist)} \longrightarrow CH_3CH_2OH + AgBr$

The reaction,water gas $(CO + H_2) + H_2$ at $673 \ K$ and $300 \ \text{atm}$ in the presence of the catalyst $Cr_2O_3/ZnO$ is used for the manufacture of:

What are $X$ and $Y$ in the following reactions?
$CH_2O \xrightarrow[(ii) H_3O^+]{(i) X} CH_3(CH_2)_2CH_2OH$
$Y \xrightarrow[(ii) H_3O^+]{(i) C_2H_5MgBr} CH_3CH_2C(CH_3)_2OH$

Explain the process of obtaining alcohols from aldehydes and ketones with examples.