In an experiment, 0.32 g of sulphur on burning in air produces 224 ml of SO2 at NTP. In another experiment, a metal sulphite reacts with a mineral acid to produce SO2, gas which contains 50% sulphur. Show that the data illustrates the law of constant composition.

In first experiment,

224ml of So2 contains .32g of S

so,22400ml contains 32g of S

 

so, the ration between S and O in SO2 is 32:32 = 1:1

Similarly in second experiment ,the SO2 contains 50 % of S so it contains 50% of O also

so the ratio between S:O  = 50:50 = 1:1

So,in both the cases the ratio between S and O in SO2 remains constant so these data are in agreement with the law of constant proportion.