$\left[\mathrm{P}\right]$ on treatment with ${\mathrm{B}\mathrm{r}}_2/{\mathrm{F}\mathrm{e}\mathrm{B}\mathrm{r}}_3$ in ${\mathrm{C}\mathrm{C}\mathrm{l}}_4$ produced a single isomer ${\mathrm{C}}_8{\mathrm{H}}_7{\mathrm{O}}_2\mathrm{B}\mathrm{r}$ while heating $\left[P\right]$ with sodalime gave toluene. The compound $\left[P\right]$ is:

At 25°C the standard emf of cell having reactions involving two electrons change is found to be 0.295 V. The equilibrium constant of the reaction is :

Kindly consider the following 

Which of the following will not give ether as product :-

Which is most reactive towards electrophilic aromatic substitution reaction :-

Which one of the following ions is the most stable in aqueous solution ?

(At. No. Ti = 22, V = 23, Cr = 24, Mn=25)