Copper Complexes and Ammonia Reactions

The video tutorial demonstrates the complexation of copper sulfate in water, highlighting the role of ammonia as a ligand. Initially, copper sulfate forms a pale blue solution, which changes color upon the addition of ammonia due to the formation of copper hydroxide. Further addition of ammonia leads to ligand displacement, resulting in a deep cobalt blue color. The video also explores Le Chatelier's Principle, showing how adding excess ammonia shifts the equilibrium. Finally, hydrochloric acid is used to reverse the reaction, demonstrating the restoration of the original copper complex.

What is the coordination number of copper in the copper hydrate complex?

• 4

• 5

• 6

• 8

What is the initial color of the copper sulfate solution before any ammonia is added?

• Yellow

• Red

• Green

• Pale blue

What happens when ammonia is added to the copper sulfate solution?

• Copper sulfate dissolves completely

• The solution turns red

• No visible change occurs

• Copper hydroxide, an insoluble compound, forms

What happens to the copper ions when ammonia is added drop by drop?

• They form a soluble compound

• They evaporate

• They remain unchanged

• They form copper hydroxide

What color is observed when excess ammonia is added to the solution?

• Pale blue

• Yellow

• Green

• Deep cobalt blue

Which positions in the complex ion remain occupied by water after adding excess ammonia?

• Axial positions

• None of the positions

• Equatorial positions

• All positions

What is the charge of the complex ion after ammonia displaces water?

• 0

• +3

• +2

• +1

According to Le Chatelier's Principle, what effect does adding more ammonia have on the equilibrium?

• Equilibrium is destroyed

• No effect on equilibrium

• Shifts equilibrium to the right

• Shifts equilibrium to the left

How can the equilibrium be shifted back to the original copper complex?

• By adding more ammonia

• By adding hydrochloric acid

• By heating the solution

• By cooling the solution

What is the role of hydrochloric acid in reversing the reaction?

• It increases the concentration of ammonia

• It removes ammonia from the solution

• It changes the color of the solution

• It adds more copper ions