Question

How many moles of H2 can be made from complete reaction of 3.0 moles of Al?

Answer 1

Answer: 4.5 moles of $H_{2}$ can be made from complete reaction of 3.0 moles of Al.

Explanation:

The given reaction equation is as follows.

$2Al + 6HCl \rightarrow 2AlCl_{3} + 3H_{2}$

This shows that 2 moles of Al reacts with 6 moles of HCl. So, the amount of HCl required to react with 1 mole Al is three times the amount of HCl.

Therefore, 3 moles of Al will react with 9 moles of HCl to give 3 moles of $AlCl_{3}$ and $\frac{9}{2}$ moles of $H_{2}$.

The reaction equation now will be as follows.

$3Al + 9HCl \rightarrow 3AlCl_{3} + \frac{9}{2}H_{2}$

The moles $\frac{9}{2}$ can also be written as 4.5 moles.

Thus, we can conclude that 4.5 moles of $H_{2}$ can be made from complete reaction of 3.0 moles of Al.