Question

(a) Give one example, with equation, of the displacement of hydrogen by a metal from an acid.
(b) Name two metals (other than zinc and iron) which can displace hydrogen from dilute hydrochloric acid?

Answer 1

The Two Metals are Sodium and Potassium

Explanation:

• a.) $Mg +2HCl$-------->  $MgCl_2 +H_2$

Is an example of displacement of Hydrogen from Hydrochloric Acid, Chlorine displaces the hydrogen and gets attached to Magnesium.

As per the reactivity Series-  

• b.) The Reactivity goes on decreasing from Left to Right-

K -> Na -> Li -> Ca ->Mg -> Al -> C -> Zn -> Fe -> Sn -> Pb -> H -> Cu -> Hg -> Ag -> Au  

• That means - A metal reacts with other metals and displaces them from their solution or displacement reaction.

• In displacement reaction, a more reactive metal displaces a less reactive metal but a less reactive metal cannot displace a more reactive metal.

So, The name of two metals (other than zinc and iron) which can displace hydrogen from dilute hydrochloric acid are magnesium, aluminium, Calcium, Lithium, Sodium and potassium.