Question

The compound (B) is:

• A.
• B.
• C.
• D.

Answer 1

Answer: (A)

i. (A) gives colour with $FeCl _{3}$, suggesting phenolic group.
ii. (A) gives positive Tollens reagent test, suggesting (-CHO) group.
iii. (A) contains only one $(- OH )$ group, since it reacts with $1 mol$ of $CH _{3} I$ to form mono methyl ether.
iv. (A) is not steam distilled, which suggests that $(- OH )$ and (-CHO) groups are not in $o$-position.
v. Total $C$ atom and $O$ atom, $6 C$ (benzene) $+- CHO +(- OH )$ group.
vi. Formula of $(A)=C_{8} H_{8} O_{3}$
vii. To count for one additional $C$ atom and one additional $O$ atom, $\left(- OCH _{3}\right)$ group must be present in (A).
viii. A must contain



But the compound $F \left( C _{7} H _{6} Br _{2} O _{2}\right)$ contains $Br _{2}$, which is only possible with compound (II). Therefore, structure (A) is (II).
Reaction

Alternative method of solving the problem:
Start from (D) and proceed reverse to (C). (D) is obtained from (C) by HI, so two structures are possible for (A).

So, (A) is II and then proceed to find out other products.