Which represents the correct equilibrium constant expression for the reaction below? upper c u (s) plus 2 upper a g superscript plus (a q) double-headed arrow upper c u superscript 2 plus (a q) plus 2 upper a g (s). k e q equals startfraction startbracket upper c u endbracket startbracket upper a g superscript plus endbracket superscript 2 over startbracket upper c us superscript 2 plus endbracket startbracket upper a g endbracket superscript 2 endfraction. k e q equals startfraction startbracket upper c u superscript 2 plus endbracket startbracket upper a g endbracket superscript 2 over startbracket upper c u endbracket startbracket upper a g superscript plus endbracket superscript 2 endfraction. k e q equals startfraction startbracket upper a g superscript plus endbracket superscript 2 over startbracket upper c u superscript 2 plus endbracket endfraction. k e q equals startfraction startbracket upper c u superscript 2 plus endbracket over startbracket upper a g superscript plus endbracket superscript 2 endfraction.

Equilibrium constant of any reaction at the equilibrium state will be define as the ratio of the concentration of products to the concentration of the reactants.

Given chemical reaction is:

Cu(s) + 2Ag⁺(aq) ⇄ Cu²⁺(aq) + 2Ag(s)

Equilibrium constant for the above reaction will be written as:

Keq = [Cu²⁺][Ag]² / [Cu][Ag⁺]²

But in the above reaction at the product side silver is present in pure solid form and at the reactant side copper is present in pure solid form and concentration of these elements equals to one in equilibrium state, so that equation becomes:

Keq = [Cu²⁺] / [Ag⁺]²

Hence equilibrium expression for given reaction is Keq = [Cu²⁺] / [Ag⁺]².

To know more about equilibrium constant, visit the below link:
https://brainly.com/question/12858312