Chapter 3, Problem 84A

Interpretation Introduction

Interpretation:

The units of water formed by adding $100$ particles of hydrogen and $100$ particles of oxygen need to be determined.

Concept introduction:

Gay Lussac’s Law explains that when a reaction takes place, all the reactants react in definite volumes and produces the products in definite volume also.

Answer to Problem 84A

Units of water formed is $100$.

Not all the particles of both elements react.

Half of the Oxygen will remain.

Explanation of Solution

As per the balanced chemical equation:

$2H_2+O_2\to 2H_{2}O$

Two moles of hydrogen reacts with one mole of oxygen to form two moles of water.

If we add $100$ particles of hydrogen to the $100$ particles of oxygen, the units of water formed will be $100$.

Only $50$ units of oxygen will react with $100$ particles of hydrogen and the rest will remain.

The limiting reagent is Oxygen.

Conclusion

When gases react they do so in definite volume as per Gay Lussac’s Law. So here also the number of particles of hydrogen should be double to the number of particles of oxygen.