A process for treating a subterranean earth formation by includes the step of introducing a buffered acidizing treatment fluid comprising a monovalent salt of monochloroacetic acid and at least one acid into the subterranean earth formation, wherein the pH of the buffered acidizing treatment fluid is from about 1.2 to about 5. The buffered acidizing treatment fluid itself includes the monovalent salt of monochloroacetic acid, the at least one acid and optionally an element to suppress salt precipitation.