Question

If $28$ ml of nitrogen are reacted with $15$ ml of hydrogen. What is the total volume of the gas present after the reaction has occurred, assuming volumes are additive?

• A. $11$ ml
• B. $17$ ml
• C. $27$ ml
• D. $33$ ml
• E. $42$ ml

Answer 1

The correct option is D $33$ ml

Nitrogen reacts with hydrogen to produce ammonia.
$N_2+3H_2\to 2N{H}_3$

Thus 1 mole of nitrogen reacts with 3 moles of hydrogen.

Volume is directly proportional to a number of moles.

Thus 1 ml of nitrogen reacts with 3 ml of hydrogen.

Hence, 15 ml of hydrogen will react with $15\times \frac{1}{3}=5$ ml of nitrogen.
$28-5=23$ ml of nitrogen are left unreacted.

15 mL of hydrogen will produce $15\times \frac{2}{3}=10$ ml of ammonia.

The total volume of the gas present after the reaction has occurred is equal to the sum of a volume of ammonia produced and the volume of unreacted nitrogen. It is $10+23=33$ ml.

Hence, option D is correct.