UPSEE Solved Model Paper 1

C6H5COO Ag(s) ⇌ C6H5COO− (aq) + Ag+(aq) K1 = Ksp
C6H5COO−(aq)+H+(aq) ⇌ C6H5COO−(aq), K2 =

1

K

C6H5COOAg(s)+H+(aq) ⇌ C6H5(COOH)(aq)+Ag+(aq)
Where, x = solubility of C6H5COOAg in a buffer of given pH
K3 =

[C6H5COOH][Ag+]

[H+]

=

x2

[H+]

=

Ksp

Ka

[H+] = 10−pH = 10−3.19 = 10−4100.81 = 6.46×10−4
∴ x2 = [H+]

Ksp/

Ka

=

6.46×10−4×2.5×10−12

6.46×10−5

x2 = 2.5 = 10−12
∴ x= √2.5×10−12 M
So lubility of C6H5COOAg in water = √Ksp
s = √2.5×10−13 M
Thus,

x

s

= √

2.5×10−12

2.5×10−2

= √10 times = 3.16 times