The number of molecules which give the haloform test among the following molecules is $.......$.

Which of the following compounds would undergo aldol condensation,which the Cannizzaro reaction and which neither? Write the structures of the expected products of aldol condensation and Cannizzaro reaction.
$(i)$ Methanal $(ii)$ $2-$Methylpentanal $(iii)$ Benzaldehyde $(iv)$ Benzophenone $(v)$ Cyclohexanone $(vi)$ $1-$Phenylpropanone $(vii)$ Phenylacetaldehyde $(viii)$ Butan$-1-$ol $(ix)$ $2,2-$Dimethylbutanal

An organic compound $(X)$ has an empirical formula $C_4H_8O$. This gives a pale yellow precipitate with iodine in $NaOH$ solution. What is $X$?

Which one is used in the manufacture of mirrors?

Consider the following reactions:
$A$ $\xrightarrow[(i) CH_3MgBr]{(ii) H_3O^{+}} B$ $\xrightarrow[573 \text{ K}]{Cu} 2\text{-methyl-2-butene}$
The mass percentage of carbon in $A$ is:

Compounds $P$ and $R$ upon ozonolysis produce $Q$ and $S$,respectively. The molecular formula of $Q$ and $S$ is $C_8H_8O$. $Q$ undergoes Cannizzaro reaction but not haloform reaction,whereas $S$ undergoes haloform reaction but not Cannizzaro reaction.
$(i)$ $P \xrightarrow[\text{ii) } Zn / H_2O]{\text{i) } O_3 / CH_2Cl_2} \underset{(C_8H_8O)}{Q}$
$(ii)$ $R \xrightarrow[\text{ii) } Zn / H_2O]{\text{i) } O_3 / CH_2Cl_2} \underset{(C_8H_8O)}{S}$
The option$(s)$ with a suitable combination of $P$ and $R$,respectively,is(are):