Chapter 19, Problem 40A

Interpretation Introduction

Interpretation:

The chemical equation of redox reaction is to be written and also the elements included in the given process is to be categorized into oxidized and reduced.

Concept introduction:

It is based on the fact that copper reacts with air and get converted into a new substance.

Answer to Problem 40A

The reaction which takes place when copper statue reacts with air:

$2Cu+H_{2}O+C{O}_2+O_2\to CuC{O}_3.Cu{\left(OH\right)}_2$

Copper metal is oxidized to $CuC{O}_3.Cu{\left(OH\right)}_2$ and oxygen is reduced to $CuC{O}_3.Cu{\left(OH\right)}_2$

Explanation of Solution

The formation of green color is due to formation of $\stackrel{+2}{Cu}C{O}_3.\stackrel{+2}{Cu}{\left(\stackrel{-2}{O}H\right)}_2$

$2\stackrel{0}{Cu}+H_{2}O+C{O}_2+\stackrel{0}{O_2}\to \stackrel{+2}{Cu}C{O}_3.\stackrel{+2}{Cu}{\left(\stackrel{-2}{O}H\right)}_2$

Oxidation number of copper is increasing so it gets oxidized and oxygen is decreasing so it is reduced.

Conclusion

The reaction which takes place when copper statue reacts with air:

$2Cu+H_{2}O+C{O}_2+O_2\to CuC{O}_3.Cu{\left(OH\right)}_2$

Copper metal is oxidized to $CuC{O}_3.Cu{\left(OH\right)}_2$ and oxygen is reduced to $CuC{O}_3.Cu{\left(OH\right)}_2$