Chapter 21, Problem 108GQ

In 1774, C. Scheele obtained a gas by reacting pyrolusite (MnO₂) with sulfuric acid. The gas, which had been obtained that same year by Joseph Priestley by a different method, was an element, A.

(a) What is the element isolated by Scheele and Priestley?

(b) Element A combines with almost all other elements. For example, with cesium it gives a compound in which the mass percent of A is 19.39%. The element combines with hydrogen to give a compound with a mass percent of element A of 94.12%. Determine the formulas of the cesium and hydrogen compounds.

(c) The compounds of cesium and hydrogen with element A react with one another. Write a balanced equation for the reaction.