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Solution:
The molecular equation is:
[tex]K_2O(aq.)+H_2O(l)\rightarrow 2KOH(aq.)[/tex]
Now, the oxide ion reacts with water to produce hydroxide ions,
The ionic equation is:
[tex]2K^+(aq.)+O^{2-}(aq.)+H_2O(l)\rightarrow 2K^+(aq.)+2OH^-(aq.)[/tex]
The [tex]2K^+[/tex] ions are present on both the sides, so the net ionic equation becomes,
[tex]O^{2-}(aq.)+H_2O(l)\rightarrow 2OH^-(aq.)[/tex]
Now, to determine acid and base, we will look at the definitions
Acid: It is defined as proton donor that is it donates [tex]H^+[/tex] ions.
Base: It is defined as proton acceptor that is it accepts [tex]H^+[/tex] ions.
In the ionic equation, water is donating [tex]H^+[/tex] ions to [tex]O^{2-}[/tex] therefore it acts as an acid and oxide ion acts as a base.
The molecular equation for the reaction is as follows:
[tex]\boxed{{{\text{K}}_2}{\text{O}}\left( {aq} \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right) \to 2{\text{KOH}}\left( {aq} \right)}[/tex]
The net ionic equation for the reaction is as follows:
[tex]\boxed{{{\text{O}}^{2 - }}\left( {aq} \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right) \to 2{\text{O}}{{\text{H}}^ - }\left( {aq} \right)}[/tex]
[tex]{{\text{O}}^{2 - }}[/tex] ion is the base in the reaction.
Further Explanation:
Acids and bases can be defined in many ways based on different theories, which are as follows:
- According to Arrhenius theory, acid is defined as the one which produces hydrogen ions in a solution, while base is defined as the one which produces hydroxide ions in a solution.
- According to Bronsted-Lowry theory, an acid in the reaction donates a proton while a base is one that accepts a proton.
- According to Lewis theory, an acid in the reaction accepts a pair of electrons while a base donates a pair of electrons.
Double displacement reaction is defined as the reaction in which ions of two compound interchange with each other to form the product. For example, the general double displacement reaction between two compounds AX and BY is as follows:
[tex]{\text{AX}} + {\text{BY}} \to {\text{AY}} + {\text{BX}}[/tex]
The three types of equations that are used to represent the chemical reaction are as follows:
1. Molecular equation
2. Total ionic equation
3. Net ionic equation
The reactants and products remain in undissociated form in molecular equation. In the case of total ionic equation, all ions that are dissociated and present in the reaction mixture are represented while in the case of net ionic equation only the useful ions that participate in the reaction are represented.
The steps to write the molecular equation and net ionic reaction are as follows:
Step 1: Write the molecular equation for the reaction with the phases in the bracket.
In the reaction, [tex]{{\text{K}}_{\text{2}}}{\text{O}}[/tex] reacts with [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex] to form 2 moles of KOH. The balanced molecular equation of the reaction is as follows:
[tex]{{\text{K}}_2}{\text{O}}\left( {aq} \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right) \to 2{\text{KOH}}\left( {aq} \right)[/tex]
Step 2: Dissociate all the compounds with the aqueous phase to write the total ionic equation. The compounds with solid and liquid phase remain same. The total ionic equation is as follows:
[tex]{\text{2}}{{\text{K}}^ + }\left( {aq} \right) + {{\text{O}}^{2 - }}\left( {aq} \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right) \to 2{{\text{K}}^ + }\left( {aq} \right) + 2{\text{O}}{{\text{H}}^ - }\left( {aq} \right)[/tex]
Step 3: The common ions on both the sides of the reaction get cancelled out to get the net ionic equation.
[tex]\boxed{{\text{2}}{{\text{K}}^ + }\left( {aq} \right)} + {{\text{O}}^{2 - }}\left( {aq} \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right) \to \boxed{2{{\text{K}}^ + }\left( {aq} \right)} + 2{\text{O}}{{\text{H}}^ - }\left( {aq} \right)[/tex]
Therefore, the net ionic equation obtained is as follows:
[tex]{{\text{O}}^{2 - }}\left( {aq} \right) + {{\text{H}}_{\text{2}}}{\text{O}}\left( l \right) \to 2{\text{O}}{{\text{H}}^ - }\left( {aq} \right)[/tex]
According to the net ionic equation, [tex]{{\text{O}}^{2 - }}[/tex] ion accepts a proton from [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex] molecule and form [tex]{\text{O}}{{\text{H}}^ - }[/tex] ions. This also converts [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex] molecule into [tex]{\text{O}}{{\text{H}}^ - }[/tex] ions. Therefore, on the basis of Bronsted–Lowry theory [tex]{{\text{O}}^{2 - }}[/tex] ion is a base because it accepts a proton from [tex]{{\text{H}}_{\text{2}}}{\text{O}}[/tex] molecule.
Learn more:
1. Balanced chemical equation: https://brainly.com/question/1405182
2. Net ionic equation for the reaction of [tex]{\text{MgS}}{{\text{O}}_{\text{4}}}[/tex] with [tex]{\text{Sr}}{\left( {{\text{N}}{{\text{O}}_3}} \right)_2}[/tex]: https://brainly.com/question/4357519
Answer details:
Grade: High School
Subject: Chemistry
Chapter: Chemical reaction and equation
Keywords: Double displacement reaction, types of equation, molecular equation, total ionic equation, net ionic equation, K2O, H2O, OH-, O2-, acid, base, base in the reaction.
