A trisubstituted compound '$\mathrm{A}$', ${\mathrm{C}}_{10}{\mathrm{H}}_{12}{\mathrm{O}}_2$ gives neutral ${\mathrm{FeCl}}_3$ test positive. Treatment of compound '$\mathrm{A}$' with $\mathrm{NaOH}$ and ${\mathrm{CH}}_3\mathrm{Br}$ gives ${\mathrm{C}}_{11}{\mathrm{H}}_{14}{\mathrm{O}}_2$, with hydroiodic acid gives methyl iodide and with hot conc. $\mathrm{NaOH}$ gives a compound $\mathrm{B}$, ${\mathrm{C}}_{10}{\mathrm{H}}_{12}{\mathrm{O}}_2$. Compound '$\mathrm{A}$' also decolorises alkaline ${\mathrm{KMnO}}_4$. The number of $\pi$ bond/s  present in the compound '$\mathrm{A}$' is _____ .

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A:  can be easily reduced using $\mathrm{Zn}-\mathrm{Hg}/\mathrm{HCl}$ to 

Reason R: $\mathrm{Zn}-\mathrm{Hg}/\mathrm{HCl}$ is used to reduce carbonyl group to –${\mathrm{CH}}_2$ – group.

In the light of the above statements, choose the correct answer from the options given below:

Number of compounds from the following which will not dissolve in cold ${\mathrm{NaHCO}}_3$ and $\mathrm{NaOH}$ solutions but will dissolve in hot $\mathrm{NaOH}$ solution is _____ .

Consider the following reaction

$$\begin{gathered} \mathrm{Propanal}+\mathrm{Methanal}=\underset{\left(\mathrm{ii}\right) \mathrm{\Delta } \\ \left(\mathrm{iii}\right) \mathrm{NaCN} \\ \left(\mathrm{iv}\right) {\mathrm{H}}_3{\mathrm{O}}^{+}}{\overset{\left(\mathrm{i}\right) \mathrm{dil}. \mathrm{NaOH}}{\to }}\mathrm{P}\underset{\left({\mathrm{C}}_5{\mathrm{H}}_8{\mathrm{O}}_3\right)}{\mathrm{roduct} \mathrm{B}} \end{gathered}$$

The correct statement for product $B$ is. It is

 The number of molecules which gives haloform test among the following molecules is :

The structures of major products $\mathrm{A},\mathrm{B}$ and $\mathrm{C}$ in the following reaction are sequence.