It dissolves in water, forming nitric acid.
It is very hygroscopic, dissolves readily in water, and rapidly undergoes oxidation on exposure to air.
It dissolves in acids forming cobaltous salts, and on exposure to air it rapidly absorbs oxygen, turning brown in colour.
Dilute nitric acid readily dissolves the metal, with formation of nitrate Pb(N03)2.
It dissolves readily in strong nitric acid, and the helium contained is thus liberated.
