Answer to Question #70836 in General Chemistry for Ari

Question

1. What is the effect of concentration on the conductance of HCl?
2. Can you predict the conductance of solution made of 25 mL of 0.010 M NaCl and 25 mL of 0.010 M NaNO3?
3. Comment on the conductance of solution resulting from mixing 25 mL of 0.010 M NH3 and 25 mL of 0.010 M HC2H3O2. Is what you expected based on the additivity rule?

Answer 1

1. The electrical conductivity of strong electrolytes, which is maximal in infinite dilution,
decreases with increasing concentration of electrolytes.
2. To compare the conductivity of both solutions, we look at the mobility of ions in these
solutions. For Cl - mobility  0 = 76,4 and for NO 3 - mobility  0 = 71,5 so conductivity for NaCl is
higher than for NaNO 3 .
3. When diluting the solutions of weak electrolytes, their electrical conductivity increases as a
result of an increase in the degree of dissociation and reaches a maximum value for infinite
dilution. In this case, the conductivity will increase not only during the dilution of solutions, but
also by adding the mobility of the ions (the rule of additivity).