100 ~mL of 2 M of formic acid ( p K_a=3.74 ) is neutralise by NaOH , at the equivalence point pH is

Step-by-step solution

Sodium formate is present at the equivalence point. It is the salt of weak acid + strong base. So, final solution will be basic in nature. As we know pH =7+ p K_a 2 + C 2 where, C is concentration of salt. Total volume of solution =100+100=200 ~mL Concentration of salt (C)=2 100 200 =1 M pH =7+ 3.74 2 + [1] 2 pH =7+1.87+0 pH =8.87