![Q. 17 Among the following statements, (i) [NiCl4]2− (atomic number of Ni = 28) is diamagnetic (ii) Ethylamine is a weaker Lewis base compared to pyridine (iii) [NiCl2{P(C6H5)3}2] has two geometrical isomers (iv) Bond angle in H2O is greater than that in H2S, the CORRECT one is (i) (ii) (iii) (iv)](https://www.letstalkacademy.com/wp-content/uploads/2026/01/slide_17-2.png)
Q. 17 Among the following statements,
(i) [NiCl4]2− (atomic number of Ni = 28) is diamagnetic
(ii) Ethylamine is a weaker Lewis base compared to pyridine
(iii) [NiCl2{P(C6H5)3}2] has two geometrical isomers
(iv) Bond angle in H2O is greater than that in H2S,
the CORRECT one is
- (i)
- (ii)
- (iii)
- (iv)
The correct statement among the options is (iv), as confirmed by VSEPR theory and electronegativity differences.
Option (i): [NiCl₄]²⁻ Diamagnetic?
[NiCl₄]²⁻ is paramagnetic, not diamagnetic. Ni (Z=28) in +2 state has d⁸ configuration; Cl⁻ as weak field ligand yields tetrahedral sp³ hybrid, with two unpaired electrons.
Option (ii): Ethylamine Weaker Lewis Base Than Pyridine?
False—ethylamine (CH₃CH₂NH₂) is a stronger base than pyridine (C₅H₅N). Alkyl groups donate electrons, enhancing availability of N lone pair; pyridine’s sp² N lone pair delocalizes into ring, reducing basicity.
Option (iii): [NiCl₂{P(C₆H₅)₃}₂] Geometrical Isomers?
[NiCl₂(PPh₃)₂] shows cis-trans isomerism. Tetrahedral Ni(II) d⁸ with bulky phosphine ligands allows geometrical isomers, unlike simple tetrahedral complexes.
Why (iv) is Correct
Bond angle in H₂O (104.5°) > H₂S (92°). Both AX₂E₂ VSEPR, but O’s higher electronegativity pulls bond pairs closer, increasing bp-bp repulsion over lp-lp; S’s larger size reduces repulsion.
