Question

In a small-scale experiment, 10 g of $KCl{O}_3$ was carefully decomposed and 3.41 g of $O_2$ gas was collected. What are the theoretical(g), actual(g) and percent (%) yields of the reaction?

• A. 3.41 g, 3.92 g, 87%
• B. 5.57 g, 6.12 g, 68 %
• C. 3.92 g, 3.41 g, 87 %
• D. 6.59 g, 3.41 g, 34 %

Answer 1

The correct option is C 3.92 g, 3.41 g, 87 %

Reaction: $2KCl{O}_3\to 2KCl+{30}_2$
Molar mass of $KCl{O}_3=122.5$ g/mole
According to the reaction,
2 moles of $KCl{O}_3$ decomposes to 3 moles of $O_2$
$(2\times$122.5 g) $KCl{O}_3$ decomposes to $3\times$32 g of $O_2$
So, 10 g of $KCl{O}_3$ will produce $\frac{3\times 32}{2\times 122.5}\times 10=3.92$ g
Theoretical yield = 3.92 g; Actual yield = 3.41g
% yield $=\frac{\text{actual yield}}{\text{theoretical yield}}\times 100=\frac{3.41}{3.92}\times 100=87$%