Question

On adding FeCl₃ solution into NaOH solution, a possitively charged colloidal sol is obtained when the following are mixed:

• A. 100 mL of 0.1 M FeCl₃ + 100 mL of 0.1M NaOH
• B. 50 mL of 0.1 M FeCl₃ + 200 mL of 0.1M NaOH
• C. 10 mL of 0.1 M FeCl₃ + 50 mL of 0.1M NaOH
• D. 200 mL of 0.1 M FeCl₃ + 800 mL of 0.1M NaOH

Answer 1

The correct option is A

100 mL of 0.1 M FeCl₃ + 100 mL of 0.1M NaOH

Since the ppt is Fe(OH)₃, Fe⁺³ ion must be in excesses to get positively charged colloid