If water, $\ce{H2O}$ is a covalent compound formed by sharing of electrons, why is it said (in case of fuel cells) that formation of water from hydrogen and oxygen is a redox reaction (transfer of electrons, not sharing). This would make it an ionic compound.
Any insights? Note that, the concept of water being formed as a result of redox reaction is highlighted in fuel cells (which is the basic principle of fuel cells - generating electricity by exploiting this transfer of electrons).
I know how fuel cells work, and it is indeed a redox reaction; but my doubt is - can water be formed by both covalent/ ionic means? (In textbooks, or in exams when asked to identify bonding present in water); when both covalent and ionic type can be achieved in its formation? Is both "covalent" and "ionic" correct while describing the formation of $\ce{H2O}$ molecule?