The correct option is A Both assertion and reason are correct statements and reason is correct explanation of assertion.
Assertion:
Only a small amount of HCl is required in the reduction of nitro compounds to amines with Iron scrap and HCl in presence of steam because FeCl2 formed gets hydrolyzed to release hydrochloric acid during the reaction which itself can be used further to continue the reaction.
Fe+2HCl→ FeCl2+H2
(Iron scrap)
FeCl2+2H2O→ Fe(OH)2+2HCl
(Steam)
So, the assertion is correct statement.
Reason:
FeCl2 formed gets hydrolyzed and releases HCl during the reaction.
So, it can be used further in the reaction. So, the Reason is a correct statement and it explains the assertion.
Hence, both assertion and reason are correct statements and reason is the correct explanation of assertion.
Therefore option (D) is correct.