In a 6-quart Instant Pot, combine the chickpeas, baking soda, 2 teaspoons salt and 6 cups water. Lock the lid in place and move the pressure valve to Sealing. Select Pressure Cook or Manual; make sure the pressure level is set to High. Set the cooking time for 5 minutes. When pressure cooking is complete, quick-release the steam by moving the pressure valve to Venting. Press Cancel, then carefully open the pot. Using potholders, carefully remove the insert from the housing and drain the chickpeas in a colander; return the insert to the housing. Rinse the chickpeas under cool water and drain well, then return to the pot. Add 6 cups water and distribute the chickpeas in an even layer.