If the formula of water is H20 then why can\'t we combine hydrogen and oxygen and make water

If the formula of water is H20 then why can\'t we combine hydrogen and

1.	If the formula of water is H20 then why can\'t we combine hydrogen and oxygen and make water
Answer» We don\'t have sufficient technology to that socially We need 1 mole of hydrogen and 2 mole of oxygen to form a drop of water So we don\'t have enough hydrogen and oxygen to make water