It is used to electroplate tin on steel. It is used in the coloring of textiles. It is used to make silvered mirrors. A certain plastic uses it as a catalyst. It was used as a test for mercury(II) ions. If it is added to a colorless solution of mercury(II), a white solid of mercury(I) would form. If more is added, a black solid of mercury metal would be made. It turns bright purple in a solution that has gold ions in it. It is used in organic chemistry as a reducing agent.