A 0.3000-g sample of soda ash (which contains sodium carbonate) is dissolved in 50.00 mL of water. Titration with standard 0.1000 M HCl required 42.70 mL of the acid to neutralize the soda ash solution. What is the percent by mass of sodium carbonate in the soda ash sample? The molar mass of sodium carbonate is 105.99 g/mol. The equation for the reaction of sodium carbonate and hydrochloric acid is