A washing powder has sodium hydrogencarbonate, $\text{NaHCO}_3$, among its ingredients. In a titration, complete reaction of a solution containing $1.00\,\text{g}$ of this washing powder needs $7.15\,\text{cm}^3$ of $0.100\,\text{mol dm}^{-3}$ sulfuric acid. Only the sodium hydrogencarbonate in the washing powder reacts with the acid. What is the percentage by mass of sodium hydrogencarbonate in the washing powder?
- A3.0%
- B6.0%
- C12.0%
- D24.0%