1. In a bowl mix together gram flour, cooking soda, red chilli powder and salt.
2. Add sufficient water and make a thick batter (but of pouring consistency).

For the Pakodas:

1. Peel the potatoes and cut into fine round rings.
2. Soak the potato slices in water with little salt.
3. Wash the brinjals and cut into thin round rings.
4. Soak them in water with little salt. Heat oil in a kadai.
5. When the oil is sufficiently hot squeeze the water from the vegetables, dip into the gram flour mixture and deep fry on a medium flame till golden.
6. Repeat with the remaining potoato and brinjal slices.
7. Serve hot with green chutney and tomato ketchup.