Introduction
In the chemistry section of the JEE Advanced exam, questions related to solubility and complex ion equilibria may be asked. These topics are important as they help in understanding the behavior of substances in solution and the formation of complex ions.

Solubility Equilibria
1. Definition: Solubility equilibria deal with the equilibrium between a solid solute and its ions in a solution.
2. Key Points:
- Questions may focus on calculating solubility products (Ksp) for various compounds.
- Understanding factors affecting solubility, such as temperature and common ion effect, is crucial.
- Equilibrium expressions and calculations involving solubility products may be asked.

Complex Ion Equilibria
1. Definition: Complex ion equilibria involve the formation of complex ions through the interaction of metal ions with ligands.
2. Key Points:
- Questions may require knowledge of ligand substitution reactions, including writing balanced equations and determining equilibrium constants.
- Understanding the concept of stability constants (Kf) and its relation to complex formation is important.
- Calculations involving complex equilibria, such as determining the concentration of free metal ions or the formation of complexes, may be asked.

Sample Questions
1. Calculate the solubility product of silver chloride (AgCl) given that the solubility of AgCl is 1.3 × 10^−5 M.
2. A solution contains 0.1 M of silver nitrate (AgNO3) and 0.05 M of ammonia (NH3). Calculate the concentration of Ag(NH3)2+ complex ion formed, given that the stability constant (Kf) is 1.6 × 10^7.

Conclusion
In the chemistry section of the JEE Advanced exam, questions related to solubility and complex ion equilibria may be asked. It is important to have a thorough understanding of these topics, including solubility products, factors affecting solubility, ligand substitution reactions, stability constants, and calculations involving complex equilibria. Practicing sample questions and solving numerical problems will help in mastering these concepts and performing well in the exam.