Question

Name the metals which displace hydrogen from acids.

Answer 1

1. An acid is a hydrogen-containing compound that gives hydronium ions $\left({\mathrm{H}}_3{\mathrm{O}}^{+}\right.$or $\left.{\mathrm{H}}^{+}\left(aq\right)\right)$ when dissolved in water.
2. An acid reacts with most metals to form corresponding salt and hydrogen gas.
3. Generally, those metals are more reactive than hydrogen.
4. They can displace hydrogen $\left({\mathrm{H}}^{+}\right)$ions from the acid
5. Examples: 1. $\underset{\left(\mathrm{magnesium}\right)}{\mathrm{Mg}\left(\mathrm{s}\right)}+\underset{(\mathrm{Hydrochloric}\mathrm{acid})}{2\mathrm{HCl}\left(\mathrm{aq}\right)}⟶\underset{(\mathrm{Magnesium}\mathrm{chloride})}{{\mathrm{MgCl}}_2\left(\mathrm{aq}\right)}+\underset{\left(\mathrm{Hydrogen}\right)}{{\mathrm{H}}_2\left(\mathrm{g}\right)}$

2. $\underset{\left(\mathrm{Iron}\right)}{\mathrm{Fe}\left(\mathrm{s}\right)}+\underset{(\mathrm{Sulphuric}\mathrm{acid})}{{\mathrm{H}}_2{\mathrm{SO}}_4(\mathrm{aq}})⟶\underset{(\mathrm{Ferrous}\mathrm{sulphate})}{{\mathrm{FeSO}}_4\left(\mathrm{aq}\right)}+\underset{\left(\mathrm{Hydrogen}\right)}{{\mathrm{H}}_2\left(\mathrm{g}\right)}$

Hence, metals like magnesium, calcium, aluminum, zinc, iron, etc. which are more reactive can displace hydrogen from acids.