[necroramo]

Which of the following would form a buffer if added to 640.0 mL of .40 M Sr(OH)2?

a. 1.00 mol of HF
b. .75 mol of HF
c. .30 mol of HF
d. 30 mol of NaF
e. .30 mol of HCL

The book doesn't say directly how to do this kind of problem and after a day of cramming I can't seem to infer it from anything.... how do I do this thing?!

[AWK]

Do you know a definition of buffer?
Do you know product of neutralization reactions beween HF or HCl with Sr(OH)₂
Note SrF₂ is insoluble in water!