The molar mass of water is calculated as follows: H (1 g/mol) x 2 + O (16 g/mol) = 18 g/mol.

In NaH (sodium hydride), hydrogen has an oxidation state of -1.

The bond angle in H2O is approximately 104.5 degrees due to the bent shape of the molecule caused by the two lone pairs on the oxygen atom.

In the complex [Ni(H2)6], the coordination number of hydrogen is 6, as there are six hydrogen ligands coordinated to nickel.

The formula for the compound formed between hydrogen and sulfur is H2S (hydrogen sulfide).

The molecular formula of the compound formed when hydrogen reacts with chlorine is HCl (hydrochloric acid).

In HCl, hydrogen has an oxidation state of +1.

In sodium hydride (NaH), hydrogen has an oxidation state of -1 because it is bonded to a metal.

The standard enthalpy change for the formation of water (H2 + 0.5 O2 -> H2O) is -285.8 kJ/mol.

The standard reduction potential for the half-reaction H2 → 2H+ + 2e- is defined as 0.00 V.