UPSEE Solved Model Paper 3

Once NaOH is added the solution becomes a buffer
CH3COOH+NaOH → CH3COONa+H2O

0.1M	0.5M	0
1 4	0.1 −0.1×1 4	0.1×1 4

neutralized

3 4

0.1− 0.1×3 4

0.1×3 4

is neutralized
(pH)

1

4

= pKa+log

[CH3COONa]

[CH3COOH]

pKa+log‌

0.1 4

0.4−0.1 4

= pKa+log‌

1

3

Similarly , (pH)

3

4

= pKa+log‌

0.3 4

0.4−0.3 4

= pKa+og‌

3

1

∴ ΔpH (by Hendersnon's equation)
= log(

3

1

)−log(

1

3

)
= 2 log 3
= 2 × 0.4771
= 0.9542