When 0.1 mol CoCl3(NH3)5 is treated with an excess of AgNO3, 0.2 mol of AgCl are obtained. The conductivity of the solution will correspond to-

1. 1:3 electrolyte

2. 1:2 electrolyte

3. 1:1 electrolyte

4. 3:1 electrolyte

Hint: Two chlorine atoms are present outside the complex.
Step 1:

One mole of AgNO3 precipitates one mole of chloride ion. ln the above reaction, when 0.1 moles Co(NH3)5Cl3

is treated with an excess of AgNO3 0.2 mole of AgCl are obtained thus, there must be two free chloride ions in the

solution of electrolyte.

Step 2:

So, the molecular formula of the complex will be [Co(NH3)5Cl]Cl2 and an electrolytic solution that must contain [Co(NH3)5Cl]2+ and two Cl- as constituent ions. Thus, it is a 1:2 electrolyte. 

The reaction is as follows:

[Co(NH3)5Cl]Cl2 (s) [Co(NH3)5Cl]2+(aq) + 2Cl-(aq)

Hence, option (b) is correct.