4.59P - Chemistry: Molecular Nature Of Matter And Change

Question

Is the following a redox reaction? Explain

 

${\mathbf{\text{NH}}}_{\mathbf{\text{3}}}\left(\text{aq}\right)\mathbf{\text{ + HCl}}\left(\text{aq}\right)\mathbf{\to }{\mathbf{\text{ NH}}}_{\mathbf{\text{4}}}\mathbf{\text{Cl}}\left(\text{aq}\right)$

Step-by-Step Solution

Answer

No, this is not a redox reaction.

Definition of redox reaction

Oxidation-reduction (or redox) reactions are a type of  chemical reaction in which the net movement of electrons from one reactant to the other occurs. 

Such movement of electron charge occurs in the formation of both ionic and covalent compounds.

Or we can say that a reaction in which one compound oxidizes and the other is reduced simultaneously in the same reaction and elements change their oxidation state in a chemical reaction are known as redox reactions.

Example: $2\mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{MgO}\left(\mathrm{s}\right)$

Determine the types of reaction when ammonia reacts with hydrochloric acid

${\mathrm{NH}}_3\left(\mathrm{aq}\right)+\mathrm{HCl}\left(\mathrm{aq}\right)\to {\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{aq}\right)$

No, this is not a redox reaction because in the redox reaction two or more elements must change their oxidation states. 

In the above reaction there is no change in oxidation state of the elements. Consequently there is no net movement of electrons in the above reaction.

This is a neutralization reaction between an acid and a base.