Number of isomeric compounds with molecular formula $C_9H_{10}O$ which $(i)$ do not dissolve in $NaOH$ $(ii)$ do not dissolve in $HCl$ $(iii)$ do not give orange precipitate with $2,4-DNP$ $(iv)$ on hydrogenation give identical compound with molecular formula $C_9H_{12}O$ is $...........$

$A$ new carbon-carbon bond formation is possible in

Match each of the compounds given in Column $I$ with the reaction$(s)$ that they can undergo,given in Column $II$.
| Column $I$ | Column $II$ |
| :--- | :--- |
| $(A)$ $3-$bromobenzofuran derivative | $(p)$ Nucleophilic substitution |
| $(B)$ Benzyl alcohol | $(q)$ Elimination |
| $(C)$ Salicylaldehyde | $(r)$ Nucleophilic addition |
| $(D)$ $1-$bromo$-2-$nitrobenzene | $(s)$ Esterification with acetic anhydride |
| | $(t)$ Dehydrogenation |

Which of the following compounds has the most acidic hydrogen?

Sum of number of $1^o$ alcoholic groups in product $(P)$ and $(Q)$ is

What is the product of the reaction shown below?