How many moles of oxygen are formed when an electric current is passed through water in the amount of 3 moles?

1. We compose the reaction equation:

2 H2O = 2 H2 + O2 (The reaction proceeds under the action of an electric current – this must be indicated above the arrow in the equation)

According to the equation: water – 2 mol, and oxygen – 1 mol

2. We calculate the amount of substance O2, making up the proportion:

3 mol Н2О – х mol О2

2 mol Н2О – 1 mol О2

Hence, x = 3 * 1/2 = 1.5 mol.