A gaseous mixture containing 50 mol% hydrogen

A gaseous mixture containing 50 mol% hydrogen and 50 mol% acetaldehyde (C2H4O) is initially
contained in a rigid container at a total pressure of 760 mmHg absolute. The formation of ethanol
occurs according to
C2H4O + H2  C2H6O
After some time, it was noted that the total pressure in the vessel had dropped to 700 mmHg
absolute. Calculate the degree of completion of the reaction, at that time, under the following
assumptions: (a) all reactants and products are in the gaseous state, and (b) the gaseous mixtures
were at the same temperature when the pressures were measured.