A solution of sodium carbonate of concentration 0.100moldm-3 is used to standardize a solution of hydrochloric acid. 25cm3 of the standard solution of sodium carbonate require 35cm3 of the acid for neutralization. Calculate the concentration of the acid.

Abeaker with 2.00×102 ml of an acetic acid buffer with a ph of 5.000 is sitting on a benchtop. the total molarity of acid and conjugate base in this buffer is 0.100 m. a student adds 4.70 ml of a 0.360 m hcl solution to the beaker. how much will the ph change? the pka of acetic acid is 4.740.