Olefin $\mathrm{A}$ gives $2$ moles acetone and one mole glyoxal on ozonolysis. The structure of $\mathrm{A}$. 

Consider the following reaction

The product $\left[A\right]$ is

Consider the following reaction:

The product $\left(\mathrm{Y}\right)$ is

$\mathrm{A} \mathrm{is}$

Consider the following statements:

1. Toluene may be oxidised to benzaldehyde by the use of ${\mathrm{CrO}}_2{\mathrm{Cl}}_2$.

2. Nitration of benzene is electrophilic addition reaction.

3. The function of anhydrous ${\mathrm{AlCl}}_3$ in Friedel-Craft reaction is to absorb water.

4. Nitration of benzene is carried out by a mixture of conc. ${\mathrm{HNO}}_3$ and conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$.

The wrong statements are