Question

The reaction, $2C+O_2\to 2CO$ is carried out by taking $24\text{g}$ carbon and $128\text{g}$ of $O_2$. Find the incorrect statements.

• A. Oxygen is the limiting reagent
• B. Amount of oxygen left is $96\text{g}$
• C. Amount of $CO$ formed is $56\text{g}$
• D. $6\text{moles}$ of carbon are required to completely react with $128\text{g}$ of $O_2$

Answer 1

Answer: (A), (D)

$6\text{moles}$ of carbon are required to completely react with $128\text{g}$ of $O_2$

Moles of Carbon $=\frac{24}{12}=2\text{mol}$
Moles of Oxygen $=\frac{128}{32}=4\text{mol}$

$\begin{array}{cccccc}& 2C& +& O_2& \to & 2CO\\ \text{Mole before reaction}& 2& & 4& & 0\\ \text{Mole before reaction}& 0& & 3& & 2\end{array}$
As per stoichiometry,
$2\text{mol}$ of carbon requires $1\text{mol}$ of $O_2$
So, $O_2$ is left in excess.
Moles of $O_2$ left = $4-1=3\text{mol}$
Amount of oxygen left $=3\times 32=96\text{g}$
Amount of CO formed $=2\times 28=56\text{g}$
$1\text{mol}$ of $O_2$ is required to react with $2\text{mol}$ of Carbon
$4\text{mol}$ of $O_2$ will require $=8\text{mol}$ of carbon
Carbon required to completely finish $4\text{mol}$ of $O_2$ will be $8\text{moles}$