A black metal oxide XO₂ is used as a catalyst in the preparation of oxygen gas from potassium chlorate. The oxide XO₂ is also used in ordinary dry cells. The metal oxide XO₂ cannot be reduced satisfactorily with carbon to form metal X.

(a) Name the metal X.

(b) Name the metal oxide XO₂

(c) Which reducing agent can be used to reduce XO₂ to obtain metal X?

(d) Name another metal which can also be extracted by the reduction of its oxide with the above reducing agent.