0.1 m acetic acid solution is titrated against 0.1 m naoh solution find difference in ph between 1/4 and 3/4 stages of neutralisation
Answers
Answer:
Explanation:
=> According to the equation for weak acids,
Kz(HAc) = [H3O+]*[Ac-]/[HAc] ...(1)
=> So, you will have acetate buffer at 1/4 and 3/4 stage of neutralisation. and As with the buffer approximation you don’t need the volume, you can use the ratio [Ac-] : [HAc]
At 1/4 stage of neutralisation, the value of ratio [Ac-] : [HAc] is 1 : 3
At 3/4 stage of neutralisation, the value of ratio [Ac-] : [HAc] is 3 : 1
=> From the equation (1) we can derive,
pH = pKz - log [HAc]/[Ac-]
=> By calculating the pH for 1/4 and 3/4 stage, we can obtain pH difference . Thus,
pH (1/4) = 4.77 -log (3/1) and pH(3/4) = 4.77 - log(1/3)
Therefore, the difference in pH = 2*log(3) = 0.95
Hence, difference in pH between 1/4 and 3/4 stages of neutralisation is 0.95