Which of the following sets of compounds correctly illustrate the law of reciprocal proportions?
a)P2O3,PH3,H2O  b)P2O5,PH3,H2O   c)N2O5,NH3,H2O   d)N2O,NH3,H2O   e)NO2,NH3,H2O

Asked by sunil2791 | 12th Mar, 2017, 12:44: PM

Expert Answer:

In PH3 the ratio by wt. of P : H =31:3

For H2O the ratio by wt. of O: H = 16:2 = 8:1

Keeping the wt. of H(=1) fixed, the ratio by wt. of P:O = 31/3:8=31:24------(1)

In P2O5 the ratio by wt. of P:O is (2x31) :(5x16) or 62:80 or 31:40-----------(2)

Keeping the wt. of P(=31) fixed in equations (1) and (2), the ratio of oxygen is 24:40 or 3:5 which is a simple ratio.

Hence the correct answer is (a).

Answered by Vaibhav Chavan | 13th Mar, 2017, 08:47: PM