500 ml of 0.2 M HCl is mixed with 500 ml of 0.2 M CH 3 COOH .25 ml of the mixture is titrated with 0.1 M NaOH solution. By how many units does the pH change from the start to the stage when HCl is just completely neutralized. K a for acetic acid =2.0 × 10-5.

Question

500 ml of 0.2 M HCl is mixed with 500 ml of 0.2 M CH 3 COOH .25 ml of the mixture is titrated with 0.1 M NaOH solution. By how many units does the pH change from the start to the stage when HCl is just completely neutralized. K a for acetic acid =2.0 × 10-5. (A) 3.7 (B) 4.4 (C) 2.0 (D) 3.0

Tardigrade Admin · Accepted Answer

[ HCl ] text mix =0.1 and [ CH 3 COOH ] text mix =0.1 M Initial pH of the mixture =1.0 Volume of NaOH required just to neutralize HCl in 25 ml textmix =25 ml Concentration of CH 3 COH after HCl in neutralized =(25 × 0.1/50)=0.05 M [ H +] =√ K a × C =√2 × 10-5 × 0.05 =10-3 M pH =3.0 Change in pH =3.0-1.0=2.0

Q. 500ml of 0.2MHCl is mixed with 500ml of 0.2MCH3​COOH.25ml of the mixture is titrated with 0.1MNaOH solution. By how many units does the pH change from the start to the stage when HCl is just completely neutralized. Ka​ for acetic acid =2.0×10−5.

3.7

4.4

2.0

3.0

[HCl]mix ​=0.1 and [CH3​COOH]mix ​=0.1M Initial pH of the mixture =1.0 Volume of NaOH required just to neutralize HCl in 25mlmix=25ml Concentration of CH3​COH after HCl in neutralized =5025×0.1​=0.05M [H+]=Ka​×C​=2×10−5×0.05​ =10−3M pH=3.0 Change in pH=3.0−1.0=2.0