The answer in this question is 4. The required hydrogen (H2) to complete the reduction of 1 mole of (3E,5Z)-3-methylhepta-3,5-dien-1-yne is 4 hydrogen. The number of hydrogen that is require is 4 to complete reduction of 1 mole. Hydrogen is defined as a chemical element with chemical symbol of H and an atonic number of 1, described by the scientist as the most abundant element in the universe.