Tin(II) chloride
It is a colorless crystalline solid. It is a reducing agent. It is poisonous to mollusks like clams and oysters. It reacts with water to make tin(II) oxide hydrate, which is white, and hydrochloric acid. That is why tin(II) chloride is normally dissolved in hydrochloric acid. It reacts with oxygen in the air to make tin(IV) chloride and tin(IV) oxide. It reacts with silver and gold compounds to make silver and gold metal. It also reacts with ferric compounds to make ferrous compounds.