Question

7.5 gm of gas occupies 5.6 litre of volume at STP. The gas is

Answer 1

7.5 gram of gas occupies a volume of 5.6 litres at 273 K and 1 atm pressure therefore, the mass of gas that occupies the volume of 22.4 litres (that is the volume of any gas at STP)

=7.5/5.6 * 22.4

=30g.

Now the molar mass of the gas is 30.

Some gases with molar mass 30 grams is,

Nitric oxide (NO)

Aluminium trihydrate gas ( AlH3 )

Formaldehyde gas (HCHO)

Lithium oxide gas ( Li2O)

Amongst these I prefer nitrous oxide as the correct answer.