Question

10 g of Hydrogen and 64 g of Oxygen were filled in a steel vessel and exploded. Calculate the amount of water produced in the reaction.

• A. 2 mol
• B. 5 mol
• C. 3 mol
• D. 4 mol

Answer 1

The correct option is D 4 mol

Balanced reaction:
$2H_2+O_2\to 2H_{2}O$

We know that, number of moles = $\frac{Givenmass}{Molarmass}$

Number of moles of $H_2$ = $\frac{10}{2}$ = 5 mol

Number of moles of $O_2$ = $\frac{64}{32}$ = 2 mol

We know that whenever moles of more than one reactant is given, we need to determine the limiting reagent (LR) in order to find the amount of product formed in the reaction.

Calculating LR,

For Hydrogen = $\frac{numberofmoles}{stoichiometriccoefficient}$ = $\frac{5}{2}$ = 2.5

For Oxygen = $\frac{numberofmoles}{stoichiometriccoefficient}$ = $\frac{2}{1}$ = 2

Since the above ratio is less for Oxygen, the limiting reagent will be Oxygen .

As per the stoichiometry, 1 mol of $O_2$ produces 2 mol of $H_{2}O$.
Hence, 2 mol of $O_2$ will produce 4 mol of $H_{2}O$.