A mass of 1 kg is suspended by a thread. It is lifted up with an acceleration of 4.9 ms^–2, and then lowered with an acceleration of 4.9 ms^–2 . The ratio of tensions in first case to second cases is (g = 9.8 ms^–2 )

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)