Question

Use the Henderson-Hasselbalch equation to calculate the pH of a solution that is 0.140M in propanoic acid and 0.120M in potassium propanoate

Answer 1

This is nothing more than plug and chug
pH = pKa + log (base)/(acid)
base = propanoate
acid = propanoic acid
You must look up the value for pKa propanoic acid.