Sodium Bicarbonate adds sodium to the diet, and the quantity used should be kept to the minimum needed as a raising agent.
Salt, sodium chloride, is easy to add in excess to your diet. Don't add salt to cooking water as it reduces the quality of the nutrients available in vegetables. Only add the minimum quantity needed to your plate.
Salt should not be added to the food of young children, and they should not be given salted chips or other foods high in salt as their kidneys are unable to excrete the excess.