تفاعل نترات الفضة AgNO3 مع كلوريد الصوديوم

التبادل المزدوج بين محاليل الأملاح: لتعرف كيفية حدوث التبادل المزدوج بين محاليل الأملاح قم بإجراء النشاط التالى: أضف قليلا من محلول كلوريد الصوديوم NaCl إلى قليل من محلول نترات الفضة AgNO3 فى أنبوبة اختبار.ماذا تلاحظ؟ يتكون راسب أبيض من كلوريد الفضة.محلول كلوريد صوديوم + محلول نترات فضة محلول نترات صوديوم + كلوريد فضة NaCl + AgNO3----- NaNO3 + AgCl الراسب يعنى أن هذا الملح غير قابل للذوبان فى الماء فيترسب فى قاع الإناء.
لاحظ أن كل دقائق هذا التفاعل عبارة عن أيونات توجد في المحلول:
1. NaCl(aq) توجد على شكل Na+ و Cl-
2. AgNO3 توجد على شكل Ag+ و NO3-
3. NaNO3 توجد على شكل Na+ و NO3-
4. AgCl(s) هي مادة صلبة بيضاء





س\ لديك قارورتان احدهما تحتوي على بروميد البوتاسيوم والاخرى على يوديد بوتاسيوم , كيف تميز بينهما (وضح بالمعادله ) .

يضاف بروميد البوتاسيوم الى نترات الفضة فيعطي راسب أصفر باهت من بروميد الفضة

KI + AgNO3 == AgCl + KNO3

عند إضافة محلول النشادر المائي يذوب الراسب قليلاً



يضاف يوديد البوتاسيوم الى نترات الفضة فيعطي راسب أصفر من يوديد الفضة

AgNO3 + KI === KNO3+ AgI


وعند إضافة محلول النشادر المائي لا يذوب الراسب


Properties of Precipitates



Precipitates are the products of a precipitation reaction, in which certain cations and anions combine to produce and insoluble solid. The determining factors of the formation of a precipitate can vary: some depend on temperature, such as solutions used for buffers, while others are dependent only on solution concentration. The solids produced in precipitate reactions are crystalline. The solid can then be suspended throughout the liquid or it can fall to the bottom of the solution. The liquid that remains above the precipitate is called the supernatant liquid.
Here is a diagram of the formation of a precipitates in the solution.





Precipitation and Double Replacement Reactions



Most precipitation reactions that occur are almost always either single replacement reactions or double replacement reaction. Double replacement reactions make up the majority of precipitation reactions, and we will be using a double replacement reaction for this particular explination. The equation for a double-replacement reaction is as follows:

AB + CD → AD + CB

As illustrated above, a double replacement reaction occurs when two ionic reactants dissociate and bond with the respective anion or cation from the other reactant. This can be thought of as "switching partners," that is, the two pairs pictured above "lose" their partner and form a bond with a different partner:


Precipitation reactions occur when different salt solutions are mixed, which result in the formation of an insoluble salt, or precipitate. When precipitation occurs, the cation of one of the soluble salts interacts with the anion of the other soluble salt to form an insoluble salt. The other ions which remain soluble are called spectator ions.. Consider the following example when aqueous solutions of NaCl and AgNO₃ are added to each other. A white cloudy precipitate forms. What is the likely product that formed a precipitate? Consider all the ions in solution. If the positive ions approached each other, they would repel, so we can't form compounds like NaAg. The same is true of the negative ions. Ions of opposite charge can attract each other so we could reform NaCl and AgNO₃. However, these are soluble salts and would immediately dissociate again into individual ions. The other possibilities are AgCl and NaNO₃. The later would likewise dissociate since we know that Na and NO₃ are soluble. The only alternative is AgCl. We can write a series of chemical equations to explain these interactions:
molecular equation: write down the species as molecules as below-
NaCl (aq) + AgNO₃ (aq) --> AgCl (s) + NaNO₃ (aq) where the (aq) for aqueous implies that the salt is in solution as is soluble.
ionic equation: write down the species as they actually occur in the solution:
Na⁺(aq) + Cl^-(aq) + Ag⁺(aq) + NO₃^-(aq) --> AgCl(s) + Na⁺(aq) + NO₃^-(aq)
net ionic equation: remove identical ions that appear on both sides fo the ionic equation that act as "spectators" in the reaction. They are called spectator ions.
Ag⁺(aq) + Cl^-(aq) --> AgCl(s)


Explanation of Double Displacement Chemical Reaction with some Examples



Double displacement reaction will be demonstrated in a precipitation or neutralization reaction.

In a precipitation a white substance, which is not soluble in water, is formed.

A⁺ B^- + C⁺D^- A⁺D^- + B⁺C^-




Image showing double displacement reaction

For example, below, reaction produces a precipitate. Here AgCl is a white precipitate produced.


Na⁺Cl^- + Ag⁺NO^3- Na⁺NO^3- + Ag⁺Cl^-

Neutralization is also an example of double displacement reaction. In these types of reaction, an acid and a base react to form water and salt. It has no effect on the indicators and is neutral, hence the name neutralization reaction.


If we consider a single displacement reaction, here any reactive metal displaces another less reactive metal from the reaction and new products are obtained, whose property varies from the parent reactants.