Adding solvent or removing solute from a solution is called diluting. And a solution is said to be concentrated if it has more solute. The opposite of diluting is called concentrating. The measure of the amount of solute in a solution is expressed in concentration.
The question is incomplete, complete question is:
Study this chemical reaction:

Then, write balanced half-reactions describing the oxidation and reduction that happen in this reaction.
Oxidation:
Reduction:
Answer:
Oxidation taking place in given reaction :

Reduction taking place in given reaction;
Explanation:
Redox reaction is defined as the reaction in which oxidation and reduction reaction occur side by side.
Oxidation reaction is defined as the chemical reaction in which an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.
Reduction reaction is defined as the chemical reaction in which an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.


In the given reaction, iron(II) ions are getting reduced and zinc metal is getting oxidized to zinc(II) ions.
Oxidation :

Reduction ;
Answer:
3.62x10⁻⁷ = Kb
Explanation:
The acid equilibrium of a weak acid, HX, is:
HX + H₂O ⇄ X⁻ + H₃O⁺
Where Ka = [X⁻] [H₃O⁺] / [HX]
And basic equilibrium of the conjugate base, is:
X⁻ + H₂O ⇄ OH⁻ + HX
Where Kb = [OH⁻] [HX] / [X⁻]
To convert Ka to Kb we must use water equilibrium:
2H₂O ⇄ H₃O⁺ + OH⁻
Where Kw = 1x10⁻¹⁴ = [OH⁻] [H₃O⁺]
Thus, we can obtain:
Kw = Ka*Kb
Solving for Kb:
Kw / Ka = Kb
1x10⁻¹⁴ / 2.76x10⁻⁸ =
3.62x10⁻⁷ = Kb
There will be chemical reaction(equation4Na+02--2Na20