Question
Question: The solubility of \( AgCl(s) \) with solubility product \( 1.6 \times {10^{ - 10}} \) in \( 0.1M \) ...
The solubility of AgCl(s) with solubility product 1.6×10−10 in 0.1M NaCl solution would be
a) 1.6×10−11
b) Zero
c) 1.26×10−5
d) 1.6×10−9
Solution
The representation of concentration of dissolved ions raise to the power their stoichiometric coefficients is known as the solubility product. When two salts with the same ion will be given, we have to consider the total value of that ion in the solution media.
Complete step by step solution:
Solubility products can be defined as the product of the concentration of ions when dissolved in a solution raised to the power of their stoichiometric coefficients. It is denoted by Ksp and the relation can be written as;
AaBb(s)→a[A]+b[B] . For this reaction, Ksp=[A]a[B]b where a and b are the stoichiometric coefficients of the reactants.
According to the question, the concentration of NaCl is 0.1M . Thus after dissociation in solution the two ions will have 0.1M concentration.
NaCl(s)→Na+(0.1M)+Cl−(0.1M)
The next reaction of dissociation of silver chloride will be as AgCl(s)→Ag++Cl−
Initially at some concentration: s − −
After dissociation: − s (s+0.1)
Let’s say s is the concentration of ion from AgCl , the solubility product will be written as
KspAgCl=[Ag+][Cl−]
On substituting the values of concentration we get
KspAgCl=[s][s+0.1]
When two salts with the same ion are given, we have to consider the total value of concentration of that ion in the solution media. This is because in the solution as the same ion will be coming from both the salts the concentration of that ion will change drastically. Thus the total added quantity is considered to calculate the concentration of corresponding ions.
It is given that KspAgCl=1.6×10−10 , solving the equation
1.6×10−10=s(s+0.1) ⇒1.6×10−10=s2+0.1s
As the value of Ksp is very small we can neglect the value of s , thus the equation became
Hence the solubility of AgCl is 1.6×10−9 .
The correct option is (a).
Note:
The precipitate silver chloride is white in colour, formed when salt containing chloride ion is mixed with silver nitrate solution. This test is used in the qualitative analysis of anions whereas bromide and iodide form pale yellow and orangish-yellow precipitate of silver bromide and silver iodide.