Sodium hydrogen carbonate is a weak base because it is not a water soluble hydroxide.
Sodium bicarbonate (NaHCO₃) is best categorized as a salt, made from a strong base (NaOH) and a weak acid (H₂CO₃). It does not qualify as a strong acid or base, though it can act as a weak acid and a weak base. Therefore, the correct answer is e. a salt (made from an acid and a base).
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