Oxidation-reduction reactions

Exercise 10

     

Balance the following redox equation without using partial ionic equations: $HCl$ $+$ $KMnO_4$ $\longrightarrow$ $KCl$ $+$ $MnCl_2$ $+$ $H_2O$ $+$ $Cl_2$ - Look for the atoms whose oxidation number changes ! - How many electrons are exchanged by each of those atoms?

o.n.($Mn$): $7$ → $2$ : $5 e^-$ exchanged by each $Mn$ atom. o.n.($Cl$): $-1$ → $0$ : $1 e^-$ exchanged by each $Cl$ atom.

How many electrons are exchanged by a "molecule" containing these atoms?

$5 e^-$ exchanged by $KMnO_4$ $2 e^-$ exchanged by $Cl_2$.

What is the ratio of these molecules? Finish the balancing!

Ratio 5:2 $16HCl$ $+$ $2$$KMnO_4$ $\longrightarrow$ $2KCl$ $+$ $2MnCl_2$ $+$ $8H_2O$ $+$ $5$$Cl_2$