Question

Calculate the mass of potassium chloride formed and the volume of oxygen evolved at 27C and 750 mm of mercury, when 24.5 g of potassium chlorate is heated.

• A. 24.5 g, 6.48 L
• B. 19.2 g, 8.40 L
• C. 14.9 g, 7.48 L
• D. 34.53 g, 9.84 L

Answer 1

Answer: (C)

14.9 g, 7.48 L

$2KCl{O}_3\to 2KCl+3O_2$

Moles of $KCl{O}_3=\frac{24.5}{122.5}=0.2$

Moles of $KCl=0.2$

Mass of $KCl=0.2\times 74=14.9gm$

Volume of $O_2=\frac{nRT}{P}=\frac{3}{2}\times \frac{0.2\times 0.0821\times 300}{\frac{750}{760}}=7.48litres$