Question

When x grams of carbon are heated with y grams of oxygen in a closed vessel, no solid residue is left behind. Which of the following statements is correct ?

• A. y/x must lie between 1.33 and 2.67

• B. y/x must be greater than or equal 2.67.

• C. y/x must be less than or equal 1.33
• D. y/x must be greater than or equal 1.33.

Answer 1

Answer: (D)

y/x must be greater than or equal 1.33.

Answer 2

(4)

C + $\frac{1}{2}$O2$\longrightarrow$ CO .... (1)

Initial mole $\frac{y}{32}$ 0

final mole 0 $\frac{y}{32} - \left( \frac{x}{12} \right)\frac{1}{2}$

CO + $\frac{1}{2}$O2 $\longrightarrow$ CO2 .... (2)

For no solid residue C should be zero in eq. (1)

For that $\frac{y}{32} - \frac{x}{12}x\frac{1}{2} > 0$

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

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

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