Chapter 8, Problem 28A

Interpretation Introduction

Interpretation:

For the reaction $\text{Mg}\left(\text{s}\right){\text{ + Cl}}_{\text{2}}\left(\text{g}\right)\to {\text{ MgCl}}_{\text{2}}\left(\text{s}\right)$ , the number of electrons gained and lost during the reaction needs to be determined.

Concept Introduction:

Metals are good conductors of heat and electricity. In the periodic table; metals include alkali metals, alkaline earth metals, transition metals, lanthanides and actinides.

Non-metals are bad conductors of heat and electricity i.e. insulators. In the periodic table; elements which are present on the right side are non metals they are present in zigzag line.

Answer to Problem 28A

Mg loses two electrons and Cl₂ gain two electrons.

Explanation of Solution

The given reaction is shown below:

  $\text{Mg}\left(\text{s}\right){\text{ + Cl}}_{\text{2}}\left(\text{g}\right)\to {\text{ MgCl}}_{\text{2}}\left(\text{s}\right)$

Metal has tendency to lose their electrons whereas non metals has tendency to gain those electrons.

Mg is an alkali metal which has tendency to lose two electrons and show stable configuration whereas Cl is a non metal which has tendency to gain those two electrons and achieve stable noble gas configuration.

The half reaction is shown below:

  $\begin{array}{l}\text{Mg(s)}\to {\text{Mg}}^{\text{2}}{}^{\text{+}}{\text{(aq)+2e}}^{\text{-}}\\ {\text{Cl}}_{\text{2}}{\text{(g)+2e}}^{\text{-}}\to {\text{2Cl}}^{\text{-}}\text{(aq)}\end{array}$

Conclusion

Mg loses two electrons and Cl₂ gain two electrons.