A black metal oxide XO<sub>2</sub> is used as a catalyst in the preparation of oxygen gas from potassium chlorate. The oxide XO<sub>2</sub> is also used in ordinary dry cells. The metal oxide XO<sub>2</sub> cannot be reduced satisfactorily with carbon to form metal X.<b>(a)</b> Name the metal X.<br> <b>(b)</b> Name the metal oxide XO<sub>2</sub>.<br> <b>(c)</b> Which reducing agent can be used to reduce XO<sub>2</sub> to obtain metal X?<br><b>(d)</b> Name another metal which can also be extracted by the reduction of its oxide with the above reducing agent.