Identify the substrate '$A$' in the following reaction: $A \xrightarrow[ii) \Delta]{i) \text{Moist } Ag_2O} CH_3CH_2N(CH_3)_2 + CH_2 = CH_2 + H_2O$

Aniline reacts with mixed acid (conc. $HNO_3$ and conc. $H_2SO_4$) at $288 \ K$ to give $P$ $(51 \%)$,$Q$ $(47 \%)$ and $R$ $(2 \%)$. The major product$(s)$ of the following reaction sequence is (are):
$R$ $\xrightarrow[2) Br_2, CH_3CO_2H]{1) Ac_2O, \text{pyridine}}$ $\xrightarrow{3) H_3O^+}$ $\xrightarrow{4) NaNO_2, HCl / 273-278 \ K}$ $\xrightarrow{5) EtOH, \Delta}$ $\xrightarrow{6) Sn/HCl}$ $\xrightarrow{7) Br_2/H_2O \text{ (excess)}} \text{Major Product}$

Identify the final product $D$ in the following reaction sequence: $CH_3CH_2Br$ $\xrightarrow[\Delta]{Aq. KOH} A$ $\xrightarrow[\Delta]{KMnO_4/H^+} B$ $\xrightarrow[\Delta]{NH_3} C$ $\xrightarrow[alkali]{Br_2} D$

An organic compound on reaction with nitrous acid $(HNO_2)$ gives an alcohol. The organic compound can be:

The product $(B)$ of this reaction is:

Arrange the following in increasing order of basicity: $CH_3NH_2$,$(CH_3)_2NH$,$C_6H_5NH_2$,$(CH_3)_3N$.