Black coffee has a $\mathrm{pH}$ of $5$ and toothpaste has a $\mathrm{pH}$ of $8$. Identify which is more acidic and deduce how many times the $\left[{\mathrm{H}}^{+}\right]$ is greater in the more acidic product.

Which methods will distinguish between equimolar solutions of a strong base and a strong acid?

I. Add magnesium to each solution and look for the formation of gas bubbles.

II. Add aqueous sodium hydroxide to each solution and measure the temperature change.

III. Use each solution in a circuit with a battery and lamp and see bright the lamp glows.