$R$ formed in the following sequence of reaction is:

$(A)$ $\xrightarrow{NH_2OH} (B)$ $\xrightarrow{H_2SO_4} (C)$ $\xrightarrow{H_3O^{\oplus}} (D) + (E)$ $\xrightarrow{CHCl_3, KOH} CH_3-NC$ (carbylamine test). $(D)$ $\xrightarrow{SOCl_2} (F)$ $\xrightarrow{(i) PhMgBr \text{ (excess) } (ii) H^{\oplus}} (G)$ $\xrightarrow[\Delta]{H^{\oplus}} (H)$ $\xrightarrow{CH_2I_2, Zn/Cu} \text{1,1-diphenylcyclopropane}$. The molecular weight of compound $(A)$ is:

Given the reactions:
$CaOCl_2 + H_2O \longrightarrow Ca(OH)_2 + X$
$X + CH_3CHO \longrightarrow Y$
$Y + Ca(OH)_2 \longrightarrow CHCl_3$
What is '$Y$'?

Identify $A$ and $B$ in the given reaction sequence:
Cyclohexylidene ethyl acetate $\xrightarrow{A}$ Cyclohexylidene ethanol $\xrightarrow{MnO_2} B$

Which of the following is called as Mandelonitrile?

Give the conversion of the following:
$(i)$ $\text{Pent-3-en-2-one}$ from $\text{Ethanal}$
$(ii)$ $\text{Pent-2-enal}$ from $\text{Ethanal}$