The compound $(x)$ in the above reaction is:

An alkene $(A)$ $C_{16}H_{16}$ on ozonolysis gives only one product $(B)$ $C_8H_8O$. $(B)$ can also be obtained by the hydrolysis of the product obtained from the reaction between cyanobenzene and $CH_3MgBr$. $(A)$ shows geometrical isomerism and decolourises $Br_2$ water. $(B)$ on treatment with $SeO_2$ produces $(C)$. Which statement is not correct about $(B)$?

Match the following lists:

Benzene on reaction with $A$ forms acetophenone,which on reaction with $B$ forms ethylbenzene. $A$ and $B$ are:

An organic compound $(X)$ has an empirical formula $C_4H_8O$. This gives a pale yellow precipitate with iodine in $NaOH$ solution. What is $X$?

Arrange the following compounds in the increasing order of their reactivity towards the nucleophilic addition of $HCN$:
$1. HCHO$
$2. CH_3COCH_3$
$3. PhCOCH_3$
$4. PhCOPh$