Number of geometrical isomers of a complex ion [Pt(PPh?)?(Py)?Cl?]²? are x, if 1 mole of ethylenediamine replaces two weakest ligands then new complex formed has 'y' number of geometrical isomers. Find the values of x/y.

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)