Question

adrian notices a precipitate form. based on the solubility rules, the compound ( au_2co_3 ) is the solid he saw.
how should he represent this compound in a complete ionic equation?
( 2au^{+}(s)+co_{3}^{2 - }(s) )
( au_2(s)+co_3(s) )
( au_{2}^{+}(s)+co_3(s) )
( au_2co_3(s) )

Explanation:

Step1: Understand complete ionic equation rules

In a complete ionic equation, solids (precipitates) are written as the whole compound. They do not dissociate into ions.

Step2: Analyze each option

• Option 1: \(2Au^{+}(s)+CO_{3}^{2 - }(s)\) implies dissociation of the solid into ions, which is incorrect for a precipitate.
• Option 2: \(Au_{2}(s)+CO_{3}(s)\) is an incorrect representation as the formula \(Au_{2}CO_{3}\) is not split into non - existent \(Au_{2}\) and \(CO_{3}\) species.
• Option 3: \(Au_{2}^{+}(s)+CO_{3}(s)\) is also an incorrect representation. There is no \(Au_{2}^{+}\) ion and \(CO_{3}\) is not a valid species in this context.
• Option 4: \(Au_{2}CO_{3}(s)\) is correct because as a solid (precipitate), it is written as the whole compound in a complete ionic equation.

Answer:

\(Au_{2}CO_{3}(s)\) (the fourth option)