sbc 200 Lecture Notes - Lecture 12: Buffer Solution, Titration, Conjugate Acid
25 Nov 2016
School
Department
Course
Professor
Document Summary
A buffer works through the common-ion effect. Acetic acid in water dissociates slightly to produce some acetate ion: Ch3cooh(aq) + h2o(l) ch3coo- (aq) + h3o+(aq) The addition of ch3coo- reduces the % dissociation of the acid. The buffer components (ha and a- ) are able to consume small amounts of added oh- or h3o+ by a shift in equilibrium position. Since ka is constant, the [h3o+] of the solution depends on the ratio of buffer component concentrations. The henderson-hasselbalch equation ph = pka + log [base]/[acid] The buffer capacity is a measure of the strength of the buffer, its ability to maintain the ph following addition of strong acid or base. The greater the concentrations of the buffer components, the greater its capacity to resist ph changes. The closer the component concentrations are to each other, the greater the buffer capacity. The buffer range is the ph range over which the buffer is effective.
