Primary nitroalkanes on boiling with hydrochloric acid undergo hydrolysis to form

Which of the following statements is incorrect?

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):
$R$ $\xrightarrow[2) Br_2, CH_3CO_2H]{1) Ac_2O, \text{pyridine}}$ $\xrightarrow{3) H_3O^+}$ $\xrightarrow{4) NaNO_2, HCl / 273-278 \ K}$ $\xrightarrow{5) EtOH, \Delta}$ $\xrightarrow{6) Sn/HCl}$ $\xrightarrow{7) Br_2/H_2O \text{ (excess)}} \text{Major Product}$

In the following reaction,$X$ is:
$X$ $\xrightarrow{\text{Bromination}} Y$ $\xrightarrow{NaNO_2 + HCl} Z$ $\xrightarrow[C_2H_5OH]{\text{Boiling}} \text{1,3,5-Tribromobenzene}$

Which of the following compounds has the lowest $pK_{b}$ value?

Rank the following in decreasing order of their acidic strengths:
$(A)$ Tetrahydrofuran-oxonium ion
$(B)$ Pyrrolidine
$(C)$ Cyclopentanol
$(D)$ $N$-methylpyrrolidinium ion