The measured BOD values for four different water sample (A-D) are as follows

A = 3 ppm;                                      B = 18 ppm:                      C = 21 ppm;        D = 4 ppm.

The water samples which can be called as highly polluted with organic wastes, are

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)