Q. Ammonia forms the complex ion $\left\lbrack Cu\left( NH_{3} \right)_{4} \right\rbrack^{2 +}$with copper ions in alkaline solution but not in acidic solution. What is the reason for it?
A) In acidic solutions, hydration protects copper ions
B) In alkaline solution, insoluble $Ci(OH)_{2}$ is precipited which in excess of any alkali
C) Copper hydroxide is an amphoteric substance
D) In acidic solutions, protons coordinate with ammonia molecules forming $NH_{4}^{+}$ ions and $NH_{3}$ molecules are not available
Explanation
(d)
In acidic solution, proton coordinate with ammonia to form$\ NH_{4}^{+}.NH_{4}^{+}$ does not act as ligand because nitrogen atom has no lone pair of electrons which it can donate to metal atom
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.