The correct answer is Option D,MnO2 (manganese dioxide). Manganese dioxide (MnO2) is commonly used as a catalyst in the decomposition of potassium chlorate (KClO3) to release oxygen gas (O2) and form potassium chloride (KCl). The reaction can be represented by the following chemical equation: 2KClO3
MnO2
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2‌KCl+3O2 Upon heating, the presence of MnO2 lowers the activation energy of the decomposition reaction, thus enhancing the rate at which O2 is produced without the catalyst itself being consumed in the reaction. This catalytic decomposition is of particular importance in applications where a ready source of O2 is needed, such as in oxygen candles for submarines or aircraft, and in safety matches.