Question

The product $X$ and $Y$ in the following reaction sequences are:

A.

B.

C.

D.

Answer 1

In organic reactions the work of $Sn/HCl$ , tin in hydrochloric acid is to reduce all the functional groups present in it and $NaN{O_2}/HCl$ is a reagent responsible for diazotization reaction means adding the two moles of a compound through the $- N = N -$ bond.

Complete step by step answer:
As we can see that $Sn/HCl$ is added to Nitrobenzene in the starting of a sequential reaction.
The work of $Sn/HCl$ in this reaction is to simply reduce it to its lowest form.
So, $Sn/HCl$ will reduce nitrobenzene to aniline and our obtained product $X$ will be aniline.
We can also understand this diagrammatically as following:

Further we can see that $NaN{O_2}/HCl$ and $CuBr$ are introduced with heat.
So our aniline which is produced in the previous step will react with these reagents.
Firstly diazotization reaction will occur due to the presence of $NaN{O_2}/HCl$ reagent and further when it reacts with $CuBr$ and it gives bromobenzene as a product.
We can also understand this diagrammatically as following:

Hence the overall occurrence of sequential reaction is:

And our products are:

So option (B) is correct.

Note:
The basic method to solve the sequential reactions is that we should picturise the reactions in our mind and start solving them one by one. Every product of the reaction is reactant of some other reaction so if we find any one product wrong the whole sequence will damage.