Three 1.0 L buffer solutions are prepared from the weak acid HB (pK_a = 6.30) as described below.
• Buffer X: 0.50 mol HB and 0.50 mol B⁻
• Buffer Y: 0.10 mol HB and 0.10 mol B⁻
• Buffer Z: 0.50 mol HB and 0.10 mol B⁻
A total of 0.020 mol of HCl is then added to each buffer. Rank the buffers from highest to lowest final pH.
a) Y>X>Z
b) X=Y>Z
c) X>Y>Z
d) Z>Y>X