An antacid tablet with the active ingredient sodium hydrogencarbonate, NaHCO3, with a mass of 0.300 g was added to 25.00 cm3 of 0.125 mol dm−3 hydrochloric acid. After the reaction was completed, the excess hydrochloric acid required 3.55 cm3 of 0.200 mol dm−3 KOH to reach the equivalence point in a titration. Calculate the percentage of sodium hydrogencarbonate, NaHCO3, in the tablet.