Question

I gram of hydrogen combines with 15.88 gram of oxygen . 8 gram of sulphur combines with 7.92 gram of oxygen . Show that these data illustrate the law of reciprocal proportions

Answer 1

The law of the reciprocal :

The weights of two or more different elements which separately combines with a fixed weight of another element are either the same as or simple multiples of the weights of these elements when they combine among themselves.

HS : Hydrogen Sulphur

1 gram 15.88 gram

HO : Hydrogen Oxygen

1 gram 7.92 gram

The ratio of different weights of Oxygen (7.92) and Sulphur (15.88) Combining with the same weight of hydrogen is :

Oxygen : Sulphur

Approximately : 8 : 16 = 1 : 4
We also have :

SO : Sulphur Oxygen

8 7.92

The ratio of hydrogen(1) and Sulphur (8) reacting with equal weights of Oxygen is :

Hydrogen : Sulphur

1 : 8
From this we can see that the ratio of sulphur in this second ratio is a multiple of the first ratio.