Question

Name two metals which will displace hydrogen from dilute acids, and two metals which will not.

Answer 1

Displacement reaction:-

1. A reactivity series is actually an arrangement in which the metal is arranged in the descending order of its reactivities.
2. Displacement is a chemical reaction in which the one element (eg: Hydrogen, $\mathrm{H}$) is replaced by the another in the compound whose reactivity must be greater or must be present above than that one element (eg: Hydrogen, $\mathrm{H}$).
3. Generically displacement reaction can be represented as : $\mathrm{A}+\mathrm{BC}\to \mathrm{AC}+\mathrm{B}(\mathrm{where}\mathrm{A}\mathrm{is}\mathrm{more}\mathrm{reactive}\mathrm{than}\mathrm{B}\mathrm{and}\mathrm{will}\mathrm{form}\mathrm{more}\mathrm{stable}\mathrm{product})$
4. Therefore, being more reactive than Hydrogen ($\mathrm{H}$) the two metals which can replace it from dilute acids are:- Zinc ($\mathrm{Zn}$) and Magnesium ($\mathrm{Mg}$)
5. The two metals being less reactive will not replace Hydrogen ($\mathrm{H}$) from dilute acids are:- Gold ($\mathrm{Au}$) and Silver ($\mathrm{Ag}$)