Question

In the reaction ${N_2} + 3{H_2} \to 2N{H_3}$, the ratio by volume of ${N_2},{H_2},N{H_3}$ is 1:3:2.
This illustrates the law of:
A. Definite proportion
B. Multiple proportion
C. Reciprocal proportion
D. Gaseous volumes

Answer 1

We can see that when nitrogen and hydrogen with one other, volume contains a simple whole number ratio with each other. This must be given by any one of the gas laws. We have to remember that in the Haber process the ammonia is prepared by nitrogen with hydrogen which leads to an exothermic reaction.

Complete step by step answer:
We can state the law of constant proportion that a given chemical compound constantly comprises its component elements in fixed ratio. It doesn’t depend on its surface and method of preparation/synthesis.
We can state Gay lussac’s law of combining volumes that when gases react with each other, they do so in volume that bear a simple ratio to one another and to the volume of the gaseous products formed, at same temperature and pressure.
We can state that the law of multiple proportions when the same two elements sorts more than one compound, the different weights of one element which combine with the same weight of the other element are in the ratio of simple small whole numbers.
We can state the law of reciprocal proportion if two different elements react separately with a continuing mass of a third element, the ratio of the weights during which they do so are either the same as or a simple multiple of the ratio of the weights in which they combine with each other.
In the reaction, ${N_2} + 3{H_2} \to 2N{H_3}$, the ratio by volume of ${N_2},{H_2},N{H_3}$ is 1:3:2. This illustrates the law of gaseous volumes or Gay lussac’s law of combining volumes of gases.

So, the correct answer is Option D.

Note: Now we can discuss about some other gaseous laws are,
Boyle’s law: At constant temperature, the pressure and the volume of the gas are inversely related to each other. $PV = K$
Charles law: At constant pressure, the temperature and the volume of the gas are proportionally related to each other. $\dfrac{V}{T} = K$