Which from following reactions converts carbonyl group of aldehydes and ketones to methylene group on treatment with zinc amalgam and concentrated $$\mathrm{HCl}$$ ?

Which among the following compounds has highest boiling point?

Identify the product formed in the following reaction,

$$\mathrm{CH}_3-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}_2-\mathrm{CHO} \mathrm{\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{(ii)\,{H_2}{O^ + }}^{(i)\,LiAl{H_4}}}} \text {Products }$$

When alcoholic solution of an organic compound is treated with few drops of Schiff's reagent, pink colour appears. This confirms the presence of group