Calculate the volume of 1M solution of HCL needed for 1 unit shift of the pH of the following solutions:
A. 100 mL of 0.01 M solution weak acid (pKa = 6) and 0.05 M of its sodium salt
B. 0.005 M of sodium formiate and 23 g of formic acid dissolved in 100 mL of water (pKa of formic acid = 3.75)
C. 100 mL of 0.1 M ammonia solution