Compounds P and R in the following reaction are

$$\mathrm{C{H_3}CHO\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{(ii)\,{H_3}{O^ + }}^{(i)\,C{H_3}MgBr}} P\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Heat}^{conc.\,{H_2}S{O_4}}} Q\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{\matrix{ {(i)\,{B_2}{H_6}} \cr {(ii)\,{H_2}{O_2}/O{H^ - }} \cr } }} R}$$

The heating of phenyl methyl ether with HI produces an aromatic compound $$A$$ which on treatment with conc. $$\mathrm{HNO}_3$$ gives $$B$$. $$A$$ and $$B$$ respectively are

The general name of the compound formed by the reaction between aldehyde and alcohol is

The test to differentiate between pentan-2-one and pentan-3-one is