Question

which statement is true of ph buffers? (a) they consist of strong acids and strong bases. (b) they keep the ph of the blood constant. (c) they consist of weak acids and weak bases. both (a) and (b). both (b) and (c). part b a buffer consists of undissociated acid (ha) and the ion made by dissociating the acid (a-). how does this system buffer a solution against decreases in ph? (a) ha dissociates and releases h+ and a- into solution. (b) a- reacts with h+ to become ha. (c) as the solution loses h+, ha replaces the lost h+. both (a) and (c). none of the above.

Explanation:

For the first question, pH buffers consist of weak acids and their conjugate bases or weak bases and their conjugate acids. They help maintain a stable pH in solutions, including in the blood. For the second question, when there is a decrease in pH (an increase in $H^+$ concentration), the anion $A^-$ of the buffer reacts with the added $H^+$ to form the undissociated acid HA, thus resisting the pH - change.

Answer:

Part A: C. They consist of weak acids and weak bases.
Part B: B. $A^-$ reacts with $H^+$ to become HA.