Sample X is dissolved in water and then diluted to a final volume of $200\,\text{cm}^3$. The solution obtained has a concentration of $0.100\,\text{mol dm}^{-3}$ HCl. What substance is X?
- A$10\,\text{cm}^3$ of $1.00\,\text{mol dm}^{-3}$ HCl
- B$30\,\text{cm}^3$ of $0.90\,\text{mol dm}^{-3}$ HCl
- C$50\,\text{cm}^3$ of $0.40\,\text{mol dm}^{-3}$ HCl
- D$100\,\text{cm}^3$ of $0.30\,\text{mol dm}^{-3}$ HCl