Numericals.

a)  m KOH  b)  m KCl  c)  m HCl 

1) The conductivity   of a saturated solution

7) The resistance of water sample of a
swimming pool is determined by using a
of AgBr at 298 K is 8.5 107 S  cm1 . If 0Ag  conductivity cell and was found to be 9200
ohm at 298 K. The same cell dipped in 0.02 M
and 0Br  are 62 and 78 S  cm2  mol 1 ,
KCl solution has R=85 ohm. When 500 g of
respectively, then calculate the solubility and NaCl was dissolved in pool and thoroughly
Ksp of AgBr.
stirred, if showed 138.0 S  cm2  mol 1 ,
2) At 25 C ,     3.50 10  m mol
o 0
m H
2 1 2 1
and
respectively, Calculate the volume of water in
  2 1 1 pool.
  2.00 10  m mol
0 2
. If the
m OH 

6 1 1
8) The conductivity   of 103 M Na2 SO4
conductivity of pure water is 5.7 10  m ,
solution is 2.6 104 S  cm1 and increases to
determine K w (ionic product) of water.
7.0 104 S  cm1 when the solution is
saturated with CaSO4. Given m Na  and
(density of H2O = 1 g/mL) 0 
3) At 298 K, 0eq of propanoic acid is
1
0m Ca 2   are 50 and 120 S  cm2  mol 1 .
386.6 S  cm  eq . If its ionization constant
2

Calculate
(Ka) is 1.4 105 . Calculate  eq of 0.05 N a)  of only CaSO4 in the solution
propanoic acid at 298K. b) Solubility of CaSO4.
4) The conductivity of H2O in a big irregular- c) Ksp of CaSO4.
shaped vessel contained water whos 9) 0m Ag  and 0m CrO42  are 61.9
conductivity is 2.0 105 S  cm1 . 585 g of 104 S  m2  mol 1 and 120
NaCl was then added to the water and the
conductivity after the addition of NaCl is 104 S  m2  mol 1 , respectively.
3.0 105 S  cm1 . Find the capacity of the Assuming that  m differs very slightly
vessel if its fulfilled with water. Given
from 0m . Calculate the solubility of
  NaCl   150 .0 S  cm  mol .
0 2 1

Ag 2CrO4 in 10 2 M AgNO 3 solution. Given

m

5)  0
 AgNO 3 ,  HCl  and  HNO3 
0 0
are a, b
  Ag 2CrO4  = 4.32 104 S  m1mol 1 and
m m m
2 -1
and c S-cm -mol , respectively. If the
conductivity of saturated AgCl solution is   pure water   0.86 104 S  m1  mol 1 at
z S  cm 1 . Calcualte the Ksp of AgCl. 300 K.
6) The conductivity of 0.1 M KOH solution is 10) Molar conductivity of aqueous solution of
1
0.022 S  cm . When an equal volume of HA is 200 cm2 mol-1, pH of this solution is
0.1M HCl is added , the conductivity 4. Calculate the value of pKa (HA) at
decreases to 0.005 S  cm . A further
1 250C. Given m  NaA  =100 S  cm2  mol 1 ,
addition of HCl solution, the volume of which m HCl  =425 S  cm2  mol 1 , m NaCl 
is equal to that of the first portion added, the
=125 S  cm2  mol 1 .
conductivity increases to 0.017 S  cm 1 .
Calculate
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