1.
AgNO2 (s)Â Â Â Â Â =Â Â
Ag+Â Â Â
+Â Â Â Â Â Â
NO2-Â Â Â Â Â Â Â Â Â Â Â Â
K = Ksp = [Ag+][NO2-]
NO2-Â Â + H2O = HNO2
+Â Â
HO-Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
K = Kb = [HNO2][HO- ]/[ NO2-]
…………………………………………………………………………..      Â
AgNO2 (s) + H2O = Â Â Ag+Â Â Â +
  HNO2 + Â
HO-Â Â Â Â Â Â K = Ksp.Kb
Observe that:
[HNO2] = [HO-]
And [Ag+] = [NO2-] =
(Ksp)1/2
Ksp.Kb = [Ag+][HNO2][HO-]
1x10-14Ksp/Ka = (Ksp)1/2 x
[HO-]2
1x10-14Ksp1/2/Ka = [HO-]2
[HO-]2 =
1x10-14x(6.1x10-4)1/2/10-3.4
          Â
= 2.45x10-16 / 4.0x10-4
          Â
= 61.25x10-14
[HO-] = 7.8x10-7 M
[H+] = 1x10-14/7.8x10-7 =
1.3x10-8 M
pH = -log[H+] = 7.9
Reload q2 as separate post.
