Heavy Water is
Answer: (3) deuterium oxide.
Heavy water is deuterium oxide.
Heavy water consists of heavy hydrogen or deuterium and oxygen. It is also known as hard water and chemical formula is D2O. Deuterium differs from the hydrogen usually found in water. It’s density is 1.107 gm/cm3 and boiling point is 101.4oC.
It makes up a small percentage (0.02%) of water naturally founded on Earth.