At 300 K, the molar conductivities of the aqueous solutions of three salts at two different concentrations are given below: array|c|c|c| Salt & Concentration (M) & Molar conductivity ( S cm2 mol-1) \ NaNO3 & 0.01 & 111 \ & 0.04 & 101 \ NaCl & 0.01 & 117 \ & 0.04 & 107 \ AgNO3 & 0.01 & 125 \ & 0.04 & 116 \ array The conductivity of a saturated aqueous solution of AgCl is 1.40 10-6 S cm-1 at 300 K. If the solubility of AgCl in water at 300 K is X mol L-1, then 10(X-1) is (Assume that AgCl dissolved in water ionizes completely and that the molar conductivity of saturated AgCl solution is equal to its limiting molar conductivity.)
- 3
- 4
- 5
- 6
Answer
(3) 5
Solution
Strong electrolytes obey Kohlrausch's law: m= m -A c; c=0.1 and 0.2.
NaNO3: slope = 111-1010.1=100, so =111+10=121; similarly NaCl: 117+10=127; AgNO3: 125+9=134 S cm2 mol-1.
(AgCl)= (AgNO3)+ (NaCl)- (NaNO3)=134+127-121=140 S cm2 mol-1
X= 1000 = 1000 1.40 10-6140=1.0 10-5 mol L-1
10(X-1)=5
Answer: (C)