A Mixture of KCl and KClO₃ Weighing 1

question 2

Multiple Choice

A mixture of KCl and KClO₃ weighing 1.80 g was heated; the dry O₂ generated occupied 1.40 × 10² mL at STP. What percent of the original mixture was KClO₃? KClO₃ decomposes as follows:
2KClO₃(s) → 2KCl(s) + 3O₂(g)

• A) 37.2%
• B) 72.6%
• C) 42.6%
• D) 63.8%
• E) 28.4%