Statement I : Oxygen gas is easily produced at a faster rate by heating a mixture of potassium chlorate and manganese dioxide than heating potassium chlorate alone. Statement I : Manganese dioxide acts as a negative catalyst.

Statement I is true because the thermal decomposition of potassium chlorate (KClO3) to produce oxygen gas is naturally a slow process. The addition of manganese dioxide (MnO2) significantly increases the reaction rate, allowing oxygen to be evolved more rapidly and at a lower temperature. Statement II is false because manganese dioxide acts as a positive catalyst, not a negative one. A positive catalyst increases the rate of a chemical reaction by lowering the activation energy barrier. In contrast, a negative catalyst (or inhibitor) would decrease the reaction rate. In this specific laboratory preparation of oxygen, MnO2 remains chemically unchanged in mass and composition at the end of the reaction, fulfilling the definition of a catalyst that speeds up the process. Therefore, while Statement I correctly describes the observed chemical behavior, Statement II incorrectly identifies the type of catalysis involved.