29. Commercially, hydrogen peroxide is generally sold as its percentage solution. For example 10 volume of hydrogen peroxide means that 1 liter of this hydrogen peroxide solution will give 10 liter of oxygen at STP
30. Hydrogen peroxide decomposes to form water and oxygen, on exposure to sunlight. Hence it is stored in wax-lined glass or plastic vessel
31. D2O is called heavy water. It is manufactured by electrolytic enrichment of normal water. It is used as moderator in nuclear reactor