Question

Methanol, is made by using a catalyst to react carbon monoxide with hydrogen at high temperature and pressure. Assuming that 450.0 of CO and 825 of H2O are allowed to react, answer the following questions. (Hint: First write the balanced chemical equation for this reaction.)
Which reactant is in excess?

Answer 1

The question is incomplete, here is the complete question:

Methanol, is made by using a catalyst to react carbon monoxide with hydrogen at high temperature and pressure. Assuming that 450.0 mL of CO and 825 mL of $H_2$ are allowed to react, answer the following questions. (Hint: First write the balanced chemical equation for this reaction.)

Which reactant is in excess?

Answer: The excess reactant in the reaction is carbon monoxide.

Explanation:

Excess reactant is defined as the reactant which is present in large amount in a reaction. The formation of product does not depend on this reactant and some amount of it remains after the completion of the reaction.

We are given:

Mass of CO = 450.0 mL

Mass of hydrogen gas = 825 mL

The balanced chemical equation for the reaction of carbon monoxide and hydrogen gas follows:

$CO+2H_2\rightarrow CH_3OH$

By Stoichiometry of the reaction:

2 mL of hydrogen gas reacts with 1 mL of carbon monoxide

So, 825 mL of hydrogen gas will react with = $\frac{1}{2}\times 825=412.5mL$ of carbon monoxide

As, given amount of carbon monoxide is more than the required amount. So, it is considered as an excess reagent.

Hydrogen gas is considered as a limiting reagent because it limits the formation of product.

Hence, the excess reactant in the reaction is carbon monoxide.