Which statement is not correct about ${\mathrm{CH}}_2={\mathrm{CCl}}_2 ?$

Select the correct statements from the following:

Find the value of $\mathrm{n}$ in the reaction: ${\mathrm{MnO}}_4^{-}+8{\mathrm{H}}^{+}+{\mathrm{ne}}^{-}⟶{\mathrm{Mn}}^{2+}+4{\mathrm{H}}_2\mathrm{O}$

Balance the following equations :

${\mathrm{BaCrO}}_4+\mathrm{KI}+\mathrm{HCl}⟶{\mathrm{BaCl}}_2+{\mathrm{I}}_2+\mathrm{KCl}+{\mathrm{CrCl}}_3+{\mathrm{H}}_2\mathrm{O}$

Balance the following reaction:

${\mathrm{SO}}_2+{\mathrm{Na}}_2{\mathrm{CrO}}_4+{\mathrm{H}}_2{\mathrm{SO}}_4⟶{\mathrm{Na}}_2{\mathrm{SO}}_4+{\mathrm{Cr}}_2{\left({\mathrm{SO}}_4\right)}_3+{\mathrm{H}}_2\mathrm{O}$

The values of$\mathrm{p}, \mathrm{q}, \mathrm{r}, \mathrm{s}$ and $\mathrm{t}$ in the following redox reaction are:

${\mathrm{pBr}}_2+{\mathrm{qOH}}^{-} \stackrel{}{\to } {\mathrm{rBr}}^{-}+{\mathrm{sBrO}}_3^{-}+{\mathrm{tH}}_2\mathrm{O}$

${\mathrm{Cr}}_2{\mathrm{O}}_7^{2-}+6{\mathrm{I}}^{-}+14{\mathrm{H}}^{+}⟶6{\mathrm{I}}_2+2{\mathrm{Cr}}^{3+}+7{\mathrm{H}}_2\mathrm{O}$

Which are not in balanced position?