# Question #90724

May 13, 2017

You figure out the amount of ${\text{O}}_{2}$ to react with 1 mol of $\text{H}$ atoms.

#### Explanation:

We can define an equivalent as the amount of a substance that can combine with or displace one mole of hydrogen atoms.

However, the number of equivalents depends on the reaction involved.

Consider this reaction.

$\text{2H"_2 + "O"_2 → 2"H"_2"O}$

It takes 4 mol of $\text{H}$ atoms to react with 1 mol of ${\text{O}}_{2}$.

So, 1 mol of $\text{H}$ atoms reacts with 0.25 mol of ${\text{O}}_{2}$.

∴ 1 eq of ${\text{O}}_{2}$ = 0.25 mol of ${\text{O}}_{2}$.

Now, consider this reaction.

${\text{H"_2 + "O"_2 → "H"_2"O}}_{2}$

It takes 2 mol of $\text{H}$ atoms to react with 1 mol of ${\text{O}}_{2}$.

So, 1 mol of $\text{H}$ atoms reacts with 0.5 mol of ${\text{O}}_{2}$.

In this reaction, 1 eq of ${\text{O}}_{2}$ = 0.5 mol of ${\text{O}}_{2}$.