In the given reaction,$[X]$ will be:

In the reaction scheme shown below,$Q$,$R$,and $S$ are the major products. Identify the correct structure of the products from the given options:
$(P)$ + Succinic anhydride $\xrightarrow{AlCl_3}$ $Q$
$Q$ $\xrightarrow[H_3PO_4]{Zn-Hg/HCl}$ $R$
$R$ $\xrightarrow[(ii) H_3O^+]{(i) CH_3MgBr, (iii) H_2SO_4/\Delta}$ $S$
$(A)$ $S$ is [Structure $A$]
$(B)$ $Q$ is [Structure $B$]
$(C)$ $R$ is [Structure $C$]
$(D)$ $S$ is [Structure $D$]

Identify the alcohol obtained when an aldehyde other than formaldehyde $(HCHO)$ is treated with Grignard's reagent $(RMgX)$ followed by hydrolysis.

Fehling solution reacts with $HCHO$ to form a precipitate of which color?

The major product formed in the following reaction is:

In the above reaction,product $(B)$ is: