Question

A 1.0 L buffer solution is 0.060 MHC2H3O2 and 0.250 MLiC2H3O2. Which of the following actions will destroy the buffer?

adding 0.060 moles of HCL

adding 0.060 moles of LiOH

Adding 0.060 moles of LiC2H3O2

Adding 0.060 moles of HC2H3O2

none of the above

Answer 1

initially

mol of acid = 0.6

mol of acetate = 0.25

so...

if we add: 0.06 mol of HCl, 0.25 M react with 0.06 M to form 0.19 M of acetate + 0.12 M of acid, there is still a buffer

b)

addition of LiOH --> this amount is enough to destroy all the weak acid present, so only conjguate base will exist, no buffer form, i.e. it is destroyed

c)

addition of 0.06 mol of acetate, will make the buffer slightly more basic, but still exists

d)

addition of more acid will make the buffer more acidic, but sill be a buffer