Chapter 20, Problem 82A

Interpretation Introduction

Interpretation: The method that can be used to remove black tarnish formed on the silver artifacts is to be explained.

Concept introduction: The reaction of silver with the sulfur present in the air results in the oxidation of silver, Ag. This caused a black-colored material on the surface of artifacts made up of silver. The reaction is,

  $2Ag\left(s\right)+H_{2}S\left(g\right)\to A{g}_{2}S\left(s\right)+H_2\left(g\right)$

Answer to Problem 82A

The rubbing of tarnished silver with aluminum helps to remove black tarnish from the silver.

Explanation of Solution

The oxidation of silver in the presence of air that contains sulfur is responsible for the formation of black tarnish on its surface. The black tarnish formed on the silver can be removed by reacting it with Aluminium. Such as, by rubbing it with aluminum foil. The reaction involved is,

  $3A{g}_{2}S\left(s\right)+2Al\left(s\right)\to 6Ag\left(s\right)+A{l}_2{S}_3\left(s\right)$

Thus silver is regenerated.