Answer :
Answer:
B. The coefficients for water and hydrogen are used.
Explanation:
You have the balanced chemical reaction given by the problem:
[tex]_{2}H_{2}_{(g)}+O_{2}_{(g)}=_{2}H_{2}O_{(l)}[/tex]
If the oxygen is in excess, it means that the hydrogen is the limiting reagent, so, to calculate the number of moles you can produce from 4.0 moles of hydrogen you use the stoichiometric coefficients as follows:
[tex]4.0molesH_{2}*\frac{2molesH_{2}O}{2molesH_{2}}=4.0molesH_{2}O[/tex]
So, the correct answer is B, the coefficients for water and hydrogen are used.