Element x reacts with Hydrogen gas at 200 deg celsius to form compound Y. When y is heated to a higher temperature, it decomposes to the element x and hydrogen gas in the ratio of 559ml of H2 (measured at standard temp and pressure) for 1.00g of x reacted. X also combined with chlorine to form a compound Z which contains 63.89% by mass of chlorine. Deduce identity of x.