The elements which form water are
(i) Hydrogen and oxygen.
Justification : Water has entirely different properties (i.e. is a liquid, extinguishes fire) from the elements it is made up of i.e. Hydrogen a gas catches fire oxygen a gas supporter of combustion.
1. Energy is needed to form water on combining O2 with H2.
2. We can not seperate the constituents of water by simple physical means.
