Question

Pls solve qs. no. 10

Answer 1

We know that 1 mole of any substance weighs the same as its molecular weight.

Also, 1 mole of any gas occupies a volume of 22.4 litres at NTP.

So, when 1 mole of a liquid vapourises and occupies a volume of 22.4 litres

We can say that a liquid of weight = molecular weight displaces dry air of 22.4l volume.

Given that 510mg liquid displaces 510cc or 510ml dry air. With this statement he only gave us a clue that the volume displaced and weight(which is equal to molecular weight as discussed above) are actually equal.

Thus the gas of some weight displaces dry air by occupying 22.4l of volume.

But since weight = molecular weight = volume occupied by gas

We get molecular weight of the liquid is 22.4 grams.

Hope it helps!!