Chronic exposure, however, weakens the kidneys. Sodium chloride is neutral in pH. Sodium bicarbonate is a mild alkali that can be eaten by the spoonful. In fact, it is a major ingredient in many antacid tablets. Sodium carbonate is a moderate alkali. Eating it by the spoonful would not be lethal but it would be uncomfortable.
Sodium hydroxide is a strong alkali that can eat flesh off of bones.
A spoonful would probably be lethal. Sodium cyanide does not eat flesh. You could wash your hands in it without effect. If you eat it, it's a different story. A spoonful is certainly lethal.