Reactions with sodium chloride and silver nitrate
What are the most important reactions with these substances?
Sodium chloride is a binary compound (consisting of two elements), a salt formed by the alkaline NaOH and the strong acid HCl. NaCl have no color or smell, and so without conducting qualitative reactions and tests, it is impossible to determine that sodium chloride is present in a solution. Practically all compounds with sodium and chloride ions are soluble.
Methods of determining the presence of sodium ions in a solution
There are several methods for determining the presence of sodium ions in a solution. For example, if you put crystals of sodium salt into a flame, the flame will turn yellow. A reaction can also be held in the solution – if you place a metal wire soaked in a solution of sodium salt, the flame changes its color to yellow. The salt must not contain impurities – other cations of alkaline and alkaline earth metal may conceal the color of the flame.
[How to get NaCl crystals from its solution](https://youtu.be/WhHGizrKqUU}
With potassium dihydrogen antimonate the sodium chloride solution gives the following reaction:
NaCl + КН₂SbО₄ = NaН₂SbО₄ + КCl.
White crystalline sediment of NaН₂SbО₄ forms. The reaction takes place in a neutral or weak alkaline medium without cations of other groups or ammonium ions.
Sodium salts react with uranyl zinc acetate Zn(UO₂)₃(CH₃СOО)₈ in the presence of acetic acid as follows:
NaCl + Zn(UO₂)₃(CH₃COO)₈ + СН₃СООН + 9Н₂О = NaZn(UO₂)₃ (CH₃COO)₉·9Н₂О + HCl.
More experiments with acids you can find here.
On a microcrystal glass, a yellow crystalline sediment forms that is *insoluble in acetic acid. *It is important that the solution does not contain salts of heavy metals.
Reaction between sodium chloride and silver nitrate
Sodium chloride and silver nitrate in dissolved form can react with each other in normal conditions. Both salts are soluble, but the product of their reaction, silver chloride AgCl is a salt that is insoluble in water, which precipitates after reaction in a white curd-like sediment:
NaCl + AgNO₃ = NaNO₃ + AgCl.
This is the qualitative reaction for chloride ions – silver ions always bond them into an insoluble compound.
If a qualitative reaction is used, usually to detect the presence of chloride ions the following method is used:
To 4-5 drops of the salt solution (in this case sodium chloride), 0.5 ml of diluted nitric acid and 2-3 drops of silver nitrate solution is added. On the sample glass a white curd-like sediment forms, soluble in ammonium.
How to determine the concentration of sodium chloride by reaction
By the reaction of sodium chloride with silver nitrate, not only the presence of chlorine ions can be determined, but also their concentration. Titration of a solution of sodium chloride is carried out with a solution of silver nitrate with a known concentration until the solution turns yellow-orange.
1 ml of the solution is taken, and an indicator added to it (in this case potassium chromate can be used), and titrated until the solution turns yellow-orange, after which the volume of silver nitrate used for titration is calculated. By proportion from the **law of equivalents: **
(V(NaCl) • Cₙ(NaCl) = V(AgNO₃) • Сₙ(AgNO₃)), the concentration of the initial solution can be calculated, as it is the only unknown value in the proportion).
Titration is often used in quantitative analysis to determine concentration of solutions. The reaction between sodium chloride and silver nitrate can also be used for both the quantitative and qualitative determination of the content of chlorine ions in a solution.