The opening of 200 mesh screen (Taylor series) is

The ratio of the actual mesh dimension of Taylor series to that of the next smaller screen is

Air has 21 % oxygen and 79 % nitrogen by volume. What is the average molecular weight ? (Atomic weight of O = 16, N =14)

A chemical reaction will occur spontaneously at constant pressure and temperature, if the free energy is

An ideal solution obeys

The equivalent weight of an element or a compound is equal to