H2S contains 97 .11% sulphur; SO2 contains 50% oxygen and H2O contains 11 .11% hydrogen. Thus, it follows;

H2S: 5.89 g H combines with :94.11 g S Hence,1 g H combines with = 16 gSSO2 : 50 g O combine with = 50 gSHence, 1 g O combines with = 1 gSH2O : 11.11 g H combines with = 88.89 g O1 g H combine with = 8 g OIn the two compounds H2S and H2O, the weights of S and O that combines with the fixed weight of 1g. of H are with ratio of 16:8 or 2:1 (Ratio 1)In SO2, the ratio of weight of S and O is 1:1 (Ratio II)Ratio (I) and (II) 21 and 11 are 2:1 and this is in accordance  with the  law  of reciprocal proportion.