The effect of changing the pH from 7 to 10 on the formation of a complex ion depends on the specific complex ion under consideration. Complex ions are formed when a central metal ion is surrounded by ligands, which are molecules or ions that can donate a pair of electrons to the metal ion. The formation of a complex ion can be represented by an equilibrium reaction:M^n+ + xL MLx^n-x +where M^n+ is the metal ion, L is the ligand, and MLx^n-x + is the complex ion.The formation of a complex ion is influenced by the pH of the solution, as the pH can affect the properties of the ligands and the metal ions. When the pH is increased from 7 to 10, the solution becomes more basic. This change in pH can have different effects on the complex ion formation, depending on the nature of the ligands and the metal ions involved.1. If the ligand is a weak base, the increase in pH can cause the ligand to become deprotonated, which can enhance its ability to form a complex ion with the metal ion. For example, consider the formation of a complex ion between a metal ion M^n+ and the weak base ligand, ammonia NH3 :M^n+ + xNH3 M NH3 x^n-x +At a higher pH, more ammonia molecules will be deprotonated to form NH2- ions, which can be stronger ligands than NH3. This can lead to an increase in the formation of the complex ion.2. If the metal ion can undergo hydrolysis, the increase in pH can cause the metal ion to form hydroxide complexes, which can compete with the ligand for the metal ion. For example, consider the formation of a complex ion between a metal ion M^n+ and a ligand L:M^n+ + xL MLx^n-x +At a higher pH, the metal ion can react with hydroxide ions OH- to form hydroxide complexes:M^n+ + yOH- M OH y^n-y +The formation of hydroxide complexes can reduce the concentration of the free metal ions available for complexation with the ligand L, which can decrease the formation of the complex ion MLx^n-x +.In conclusion, the effect of changing the pH from 7 to 10 on the formation of a complex ion depends on the properties of the specific complex ion under consideration. The change in pH can either enhance or decrease the formation of the complex ion, depending on the nature of the ligands and the metal ions involved.