The equation that shows {text{M}}{{text{n}}^{3 + }}  acts as the acid is

boxed{{{left[{{text{Mn}}{{left({{{text{H}}_2}{text{O}}}right)}_6}}right]}^{3 + }}+{{text{H}}_2}{text{O}}to{{left[ {{text{MnOH}}{{left({{{text{H}}_2}{text{O}}} right)}_5}}right]}^{2 + }}{{text{H}}_3}{{text{O}}^ + }}

Further Explanation:

Acids and bases can be defined in many ways based on different theories, which are as follows:

1. Arrhenius theory: According to this theory, acid is defined as the one which produces hydrogen or hydronium ions in a solution, while the base is defined as the one which produces hydroxide ions in a solution. Examples of Arrhenius acids include HBr, {text{HN}}{{text{O}}_3} and  {{text{H}}_2}{text{S}}{{text{O}}_4} while NaOH and KOH are examples of Arrhenius bases.

2. Bronsted-Lowry theory: According to this theory, the acid in the reaction donates a proton while a base is one that accepts a proton. HCl acts as Bronsted acid while {text{N}}{{text{H}}_3} is a Bronsted base.

3. Lewis theory: According to this theory, an acid accepts a pair of electrons to electron-rich species while a base donates electrons to electron-deficient species in the reaction. Examples of Lewis acids are {text{B}}{{text{F}}_3} , {text{S}}{{text{O}}_3} while {{text{H}}_2}{text{O}} and ROH are the examples of Lewis base.

The equation to show the acidic nature of {mathbf{M}}{{mathbf{n}}^{{mathbf{3 + }}}}is as follows:

{left[ {{text{Mn}}{{left({{{text{H}}_2}{text{O}}}right)}_6}}right]^{3 + }}+{{text{H}}_2}{text{O}}to {left[{{text{MnOH}}{{left( {{{text{H}}_2}{text{O}}}right)}_5}} right]^{2+}}+{{text{H}}_3}{{text{O}}^+}

Here, {text{M}}{{text{n}}^{3 + }} exists as {left[{{text{Mn}}{{left( {{{text{H}}_2}{text{O}}}right)}_6}}right]^{3 + }} in the aqueous medium. It reacts with water molecule to form {left[{{mathbf{MnOH}}{{left( {{{mathbf{H}}_{mathbf{2}}}{mathbf{O}}} right)}_{mathbf{5}}}} right]^{{mathbf{2 + }}}}and {{mathbf{H}}_{mathbf{3}}}{{mathbf{O}}^{mathbf{ + }}}is also released during the reaction.

Learn more:

1. The reason for the acidity of water brainly.com/question/1550328

2. Reason for the acidic and basic nature of amino acid brainly.com/question/5050077

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Chemical reaction and equation

Keywords: acid, Mn3+, Arrhenius theory, Bronsted-Lowry theory, Lewis theory, H3O+, HCl, NH3, BF3, SO3, hydrogen ions, hydronium ions, hydroxide ions, aqueous, water, Mn(H20)63+, MnOH(H2O)63+, H2O, accepts, donates, electrons, reaction, proton.