Question

When ${}^{\prime }{x}^{\prime }g$ of carbon is heated with ${}^{\prime }{y}^{\prime }g$ of oxygen in a closed vessel, no solid residue is left behind. Which of the following statements is correct?

• A. $\frac{y}{x}$ must lie between $1.33$ and $2.67$
• B. $\frac{y}{x}$ must be greater than or equal $2.67$
• C. $\frac{y}{x}$ must be less than or equal $1.33$
• D. $\frac{y}{x}$ must be greater than or equal $1.33$

Answer 1

The correct option is D $\frac{y}{x}$ must be greater than or equal $1.33$

Carbon reacts with oxygen to form $CO$ and $C{O}_2$.
$\begin{array}{ccccccc}& C& +& \frac{1}{2}{O}_2& \to & CO& ...\left(i\right)\\ \text{Initial mole}& \frac{x}{12}& & \frac{y}{32}& & 0& \\ \text{final mole}& 0& & \frac{y}{32}-\left(\frac{x}{12}\right)\frac{1}{2}& & & \end{array}$

$CO+\frac{1}{2}{O}_2\to C{O}_2...\left(2\right)$
For no solid residue, $C$ should be zero in eq. (1)
For that $\frac{y}{32}-\frac{x}{12}\times \frac{1}{2}>0$
$\frac{y}{32}>\frac{x}{24}$

$\frac{y}{x}>\frac{32}{24}$

$\frac{y}{x}>1.33$