Question

A 0.100 M solution of HCNO has a [H+] of 0.0045 M. A 0.100 M solution of CH3COOH has a [H+] of 0.0013 M.

a) Which acid should have a larger numerical value for KA? Defend your answer to get credit. No math needed – just explain.

b)Which acid should have a larger numerical value for KB? No math needed, just explain.

c)Which acid should have a larger numerical pKA?

d)What is the pOH of the CH3COOH solution (want a number here)?

Answer 1

Since H+ concentration is higher for HCNO in comparison to Acetic acid , HCNO has a larger numerical value for Ka.

Greater the Ka value , lower will be the value of Kb and vice versa, so, The acid whose Ka value is lower , has greater Kb value , That is why, Acetic acid has greater value of Kb.

pKa = - log Ka , Lower the Ka value , greater will be pKa and vice versa, Acetic acid has lower Ka value , it will have ,larger pKa value.