Is AgI Soluble or Insoluble? | Solubility of Silver Iodide
Silver iodide is insoluble in water and form a bright yellow precipitate in water. If it is explained in other way, you can see a bright yellow color solid is deposited at the bottom of the aqueous solution. You can verify AgI solubility by checking the solubility value and solubility product value. solubility value and solubility product value of AgI is very low compared to compounds such as NaCl, KCl.
Silver iodide is an insoluble inorganic compound and used in silver ion testing experiments in qualitative analysis.
Solubility and solubility product of AgI
Solubility and solubility product are good points to understand solubility of a compound and they can be used to AgI too.
Solubility of AgI in water
Solubility of AgI is 3 * 10-7 g/ 100 ml of water at 200C. So it is a very low value and prove furthermore, AgI is a precipitate and does not dissolve in water.
Solubility of AgI in water against temperature
When temperature increases, solubility of AgI increases.
Solubility product of AgI
Ksp of AgI is 8.25 *10-17 mol2 dm-6 which is also low and again tells us AgI is not soluble in water.
How AgI precipitate is formed in water?
When aqueous silver nitrate (AgNO3) solution is mixed with aqueous potassium iodide (KI) solution, AgI bright yellow precipitate is deposited at the bottom of the aqueous solution.
AgNO3 + KI → AgI + KNO3
With physical states
AgNO3(aq) + KI(aq) → AgI(s) + KNO3(aq)
Other halides of silver ion
Silver chloride, silver bromide and silver iodide are precipitates and very useful in identification of halide ions in qualitative analysis of inorganic chemistry. and do not dissolve in dilute acids. Also they have colors when they form precipitates.
Colors of silver halides
| Silver halide name | Chemical formula | Color |
|---|---|---|
| Silver chloride | AgCl | white |
| Silver bromide | AgBr | light yellow / pale yellow |
| Silver iodide | AgI | Yellow |
In which solutions AgI is soluble if it is not soluble in water?
AgCl is soluble in hydriodic acid (HI), /aqueous solutions of/ potassium iodide (KI), sodium chloride, potassium cyanide, ammonium hydroxide, and sodium thiosulfate.
Calculate solubility product from solubility data of AgI
From solubility data of AgI, we got an idea AgI solubility in water is very poor. Now, we are going to find out solubility product of AgI.
- Solubility of AgI = 3 * 10-7 g/ 100 ml of water
- Solubility of AgI = 3 * 10-6 g/ 1 dm3 of water
Now, we know the maximum soluble AgI mass in 1 dm3 of water. Now we are going to calculate soluble amount (mol) of AgI in 1 dm3
- Soluble amount of AgI = 3 * 10-6 g /234.77 g mol-1
- Soluble amount of AgI = 1.28 * 10-8 mol
Soluble AgI dissociate to Ag+ ions and I- ions in the water.
AgI → Ag+ + I-
- Soluble amount of Ag+ ions = 1.28 * 10-8 mol
- Soluble amount of I- ions = 1.28 * 10-8 mol
Because AgI was dissolved in 1 dm3 of water, we can write concentrations of Ag+ ion and I- ion.
- Concentration of Ag+ ions = 1.28 * 10-8 mol dm-3
- Concentration of I- ions = 1.28 * 10-8 mol dm-3
Now, we can write the equation of solubility product of AgI.
- Solubility product of AgI = [Ag+(aq)]*[Cl-(aq)]
- Solubility product of AgI = 1.28 * 10-8 mol dm-3 * 1.28 * 10-8 mol dm-3
- Solubility product of AgI = 1.64 * 10-16 mol2 dm-6
Questions
Molar solubility of AgI
How much moles of AgI dissolve in 1 dm-3 of distilled water?
Molar solubility of AgI = Solubility of AgI in grams / molar mass of AgI
- Molar solubility of AgI = 3 * 10-6 g / 234.77 g mol-1
- Molar solubility of AgI = 1.28 * 10-8 mol l-1
Is silver iodide (AgI) soluble when ammonia solution is added?
AgI is not soluble in aqueous ammonia solution like AgCl or AgBr.
How many grams of AgI dissolve in 100 ml of water?
With temperature, solubility of AgI vary. At 200C, 3 * 10-7 g of AgI is soluble in water.
What is the least soluble silver halide from AgCl, AgBr and AgI?
Compare solubility values of each compound. Solubility is given for 100 ml of water.
- AgCl - 5.20 *10-4 g/100 g of water at 500C
- AgBr - 1.40 * 10-5 g/ 100 ml of water at 200C
- AgI - 3 * 10-7g/ 100 ml of water at 200C
From available data, we can think AgCl is more soluble than AgBr and AgI.
