A student looks at two semi-precious stones; one is agate, $\text{SiO}_2$, while the other is calcite, $\text{CaCO}_3$. How might they be told apart?
- AAdd a fixed amount of cold aqueous sodium hydroxide to each separately and measure any temperature change.
- BHeat each separately over a gentle Bunsen flame and note which one melts first.
- CShake each separately with dilute hydrochloric acid and test any gas formed.
- DShake each separately with distilled water and add a few drops of Universal Indicator.