Question

Use your measured conductances for 0.025 M KCl and 0.025 M KNO3 to predict which of the following solutions has the larger conductance: 0.1 M NaCl or 0.1 M NaNO3.Explain.

0.025 M KCl: 3.30 mS
0.025 M KNO3: 3.20 mS

Answer 1

Conductance depends on number of ions and mobility of ions.
Given that
0.025 M KCl conductance = 3.30 mS
0.025 M KNO3 conductance = 3.20 mS
Both solutions have same molarity and K^+ ion as common ion. Only anion is different that shows nitrate ion (NO3-) has less conductance than chloride ion. Because nitrate ion is larger ion than chloride ion so it has less mobility and less conductance.
0.1 M NaCl and 0.1 M NaNO3 both have Na^+ ion as common ion. So only anion is different in two solutions.
∴0.1M NaCl has larger conductance than 0.1M NaNO3 as chloride ion has greater mobility than nitrate ion.