Why is it necessary to compare gases at S.T.P.?

Why is it necessary to mix gypsum with cement clinker?

Why is modulation necessary at all ?

Define S.T.P.

Why is it necessary to fuse the compound with sodium in the detection of N, S or halogens by Lassaigne's test?

Why is it necessary for a pendulum executing SHM to have its amplitude small as compared to its length ?

Why is it necessary to remove sulphur from petroleum products ?

Why is it necessary to remove sulphur from petroleum products ?

Why is it not necessary to supply nitrogenous fertilisers to the leguminous plants?

Why is cell division necessary ?

Which will have greater volume when the following gases are compared at S.T.P. (i) 1.2lN_2 at 25^@C and 748 mm Hg (ii) 1.25l O_2 at S.T.P?