Complex sentence: Concentrated hydrochloric acid dissolves many metals and forms oxidized metal chlorides and hydrogen gas, and it reacts with basic compounds such as calcium carbonate or copper (II) oxide, forming the dissolved chlorides that can be analyzed.
Split into simpler sentences: Concentrated hydrochloric acid dissolves many metals and forms oxidized metal chlorides and hydrogen gas. It also reacts with basic compounds such as calcium carbonate or copper (II) oxide, forming the dissolved chlorides that can be analyzed.