When 50 gm of a sample of sulphur was burnt in air 4% of the sample was left over. Calculate the volume of air required at STP containing 21% oxygen by volume.

When 50 gm of a sample of sulphur was burnt in air 4% of the sample wa

1.	When 50 gm of a sample of sulphur was burnt in air 4% of the sample was left over. Calculate the volume of air required at STP containing 21% oxygen by volume.
Answer» Solution :Weight of sample of sulphur TAKEN =50g PERCENTAGE of impurity =4% Weight of impurity in sample `=(4 xx 50)/(100)=2gr` Weight of sulphur in sample =50-2=49grams Combustion of sulphur GIVES sulphurdioxide `S+O_(2) to SO_(2)` 1 mole of S=1 mole of `O_(2)` 32grams of S=22.4 L of `O_(2)` at STP 48 GRAMS of S=? Volume of oxygen required at STP `=(48)/(32) xx 22.4=33.6 L` 21 L of `O_(2)` is present in 100L of air 33.6 L of `O_(2)` present in ? Volume of air required at STP `=(33.6)/(21) xx 100=160L`