Choose the correct statements from the following :
(A) Ethane-1, 2-diamine is a chelating ligand.
(B) Metallic aluminium is produced by electrolysis of aluminium oxide in presence of cryolite.
(C) Cyanide ion is used as ligand for leaching of silver.
(D) Phosphine act as a ligand in Wilkinson catalyst.
(E) The stability constants of Ca²⁺ and Mg²⁺ are similar with EDTA complexes.
Choose the correct answer from the options given below :

Solution

Chemistry ma’am · 3 steps

Test each statement against NCERT. Statement (E) is false, and only one option leaves it out.

1. Statement	True or false	Why
   (A) en is chelating	True	H₂N-CH₂-CH₂-NH₂ binds through both N atoms and forms a five-membered ring with the metal.
   (B) Al by electrolysis	True	Hall–Héroult process: Al₂O₃ is electrolysed with cryolite Na₃AlF₆, which lowers the melting point and raises conductivity.
   (C) CN⁻ leaches Ag	True	Silver dissolves as [Ag(CN)₂]⁻ in aerated cyanide solution.
   (D) Phosphine in Wilkinson	Not accepted	Wilkinson catalyst is [RhCl(PPh₃)₃]. Its ligand is triphenylphosphine, not phosphine PH₃ itself.
   (E) Similar stability constants	False	The constants for Ca²⁺ and Mg²⁺ with EDTA are different.

2. Why (E) fails. Hardness of water is found by titrating with Na₂EDTA. The two ions can be estimated selectively only because their EDTA complexes differ in stability. If the constants were similar, the titration could not tell them apart.
3. Use the options. Options (a), (b) and (c) all include (E), so all three are out. That settles the answer even before you weigh (D).
4. So. The correct statements are (A), (B) and (C), which is option (d).

The idea to keep. Ca²⁺ and Mg²⁺ are told apart by EDTA because their stability constants differ. Look for the one false statement that knocks out several options at once.

Answer from the NTA final answer key. Solution by PrepWiser.