Q. 50 cm3 of 0.2 N HCI is titrated against 0.1 N NaOH solution. The titration is discontinued after adding 50 cm3 of NaOH. The remaining titration is completed by adding 0.5 N KOH. The volume of KOH required for completing the titration is ______?

1. 25 cm3
2. 10.5 cm3
3. 12 cm3
4. 10 cm3