In an ideal gas reaction an increase in pressure at constant temperature increases the degree of reaction if the sum of the stoichiometric coefficients of the ``reactants'' is greater in absolute value than the sum of the ν's of the ``products,'' and vice versa. Prove this statement or show it to be false, using the law of mass action. What is the relation of this statement to the Le Chatelier--Braun principle (Sect. 8.5)?