Question

The pk of weak acid h a is 4.5 the ph of an aqueous buffer solution of a in which 50% of acid is ionized is​

Answer 1

ph =pka=4.5          ; this is because the ratio log [A^-]/[HA]=log o.5/0.5=0

                                       hence, ph=pka in the formulla ph=pka+log [A^-]/[HA]

hence, poh= 14-ph=14-4.5=9.5