An example where two gases [or a gas and a liquid] can be combined to make a solid?

Answer 1

Hold an open bottle of ammonia solution near an open bottle of hydrochloric acid solution.You'll get clouds of white smoke. The ammonia and hydrogen chloride are both gases. They react to give clouds of ammonium chloride particles. Ammonium Chloride is a white solid at room temperature. Xenon and oxygen are both gases at room temperature, but xenon trioxide is an explosive solid. When it explodes there's nothing left. It has decomposed into xenon and oxygen.

Answer 2

Oxygen and Hydrogen. Burn hydrogen below 32 deg F and you have ice!