The alkaline earth metal nitrate that does not crystallise with water molecules, is :

A water sample has ppm level concentration of the following metals : Fe = 0.2; Mn = 5.0; Cu = 3.0; Zn = 5.0. The metal that makes the water sample unsuitable for drinking is :

The isotopes of hydrogen are :

Correct statements among a to d regarding silicones are :

(a)   They are polymers with hydrophobic character.
(b)   They are biocompatible.
(c)   In general, they have high thermal stability and low dielectric strength.
(d)   Usually, they are resistant to oxidation and used as greases.