Which of the following compounds reacts with ethylmagnesium bromide and also decolourizes bromine water solution?

Benzoic acid gives benzene on being heated with $X$ and phenol gives benzene on being heated with $Y$. Therefore $X$ and $Y$ are respectively

Benzoic acid and salicylic acid can be distinguished by

What are $X$ and $Y$ respectively in the following set of reactions?

$A$ trisubstituted compound '$A$',$C_{10}H_{12}O_2$ gives a neutral $FeCl_3$ test positive. Treatment of compound '$A$' with $NaOH$ and $CH_3Br$ gives $C_{11}H_{14}O_2$,with hydroiodic acid $(HI)$ gives methyl iodide,and with hot conc. $NaOH$ gives a compound $B$,$C_{10}H_{12}O_2$. Compound '$A$' also decolorises alkaline $KMnO_4$. The number of $\pi$ bonds present in the compound '$A$' is $...........$

Salicylaldehyde is synthesized from phenol when reacted with: