The missing reagent is:

Which one of the following on reduction with lithium aluminium hydride yields a secondary amine?

The product$(s)$ of the following reaction sequence is(are):
Aniline $\xrightarrow[\text{ii) } KBrO_3/HBr]{\text{i) Acetic anhydride/pyridine}}$ $\xrightarrow[\text{iv) } NaNO_2/HCl, 273-278 \ K]{\text{iii) } H_3O^+, \text{heat}}$ $\xrightarrow{\text{v) } Cu/HBr} \text{Product}$

The major product ($70\%$ to $80\%$) of the reaction between $m$-dinitrobenzene with $NH_4HS$ is

In the reaction $CH_3CH_2CONH_2 \xrightarrow[Br_2]{NaOH} A$,the aqueous solution of $A$ is ............

Which of the following substances generally has the highest melting point?