key term - Silver chloride (AgCl)

Definition

Silver chloride (AgCl) is an inorganic compound formed by the reaction of silver ions and chloride ions, resulting in a white crystalline solid. This compound is known for its low solubility in water, making it a key player in precipitation reactions and influencing the common ion effect in various chemical systems.

5 Must Know Facts For Your Next Test

1. Silver chloride is poorly soluble in water, with a solubility of about 0.89 mg/L at room temperature, which makes it useful in precipitation reactions.
2. In the presence of a common ion, such as chloride, the solubility of silver chloride decreases significantly due to the common ion effect, leading to more precipitation.
3. When light strikes silver chloride, it undergoes photochemical decomposition, forming elemental silver and chlorine gas, which is why it has applications in photography.
4. The reaction between silver ions and chloride ions to form silver chloride is represented by the equation: $$ ext{Ag}^+ (aq) + ext{Cl}^- (aq) ightleftharpoons ext{AgCl} (s)$$.
5. The solubility product constant (Ksp) for silver chloride is approximately 1.77 x 10^-10 at 25°C, which quantifies its low solubility.

Review Questions

• How does the presence of a common ion affect the solubility of silver chloride?
  • The presence of a common ion, such as chloride, decreases the solubility of silver chloride due to the common ion effect. When additional chloride ions are introduced into the solution, the equilibrium shifts according to Le Chatelier's principle. This shift results in more solid AgCl precipitating out of solution as the system tries to counteract the increased concentration of chloride ions.
• Discuss the significance of the solubility product constant (Ksp) for understanding precipitation reactions involving silver chloride.
  • The solubility product constant (Ksp) for silver chloride is crucial for predicting whether a precipitate will form when solutions containing Ag+ and Cl- are mixed. A Ksp value of approximately 1.77 x 10^-10 indicates that very little AgCl will dissolve in water. If the product of the concentrations of Ag+ and Cl- exceeds this Ksp value, AgCl will precipitate out of solution, illustrating how Ksp can guide the understanding and control of precipitation reactions.
• Evaluate the role of silver chloride in both analytical chemistry and practical applications, including its unique properties.
  • Silver chloride plays an important role in analytical chemistry due to its low solubility and ability to form a precipitate. This makes it useful for qualitative analysis to detect the presence of chloride ions. Furthermore, its photochemical properties allow it to be used in photographic processes where exposure to light transforms AgCl into elemental silver. Thus, understanding its behavior in various chemical contexts enhances its applications in both lab settings and everyday products.

Related terms

Precipitation Reaction: A chemical reaction where two solutions combine to form an insoluble solid, known as a precipitate.

Common Ion Effect: The shift in equilibrium that occurs when an ion that is already part of a saturated solution is added, leading to decreased solubility of the solute.

Solubility Product Constant (Ksp):

An equilibrium constant that represents the maximum amount of a solute that can dissolve in a solution at a given temperature.