Chemistry MCQs for NEET — Practice Questions with Answers

 [Pt(en)₂Cl₂] can show optical as well as geometrical isomerism.

EAN=26-3+2$\times$6=35

a. [NiCl₄]^2-,hybridised state of Ni=sp³ shape=Tetrahedral

b. [Ni(CO)₄],hybridised state of Ni=sp³ shape=Tetrahedral

c. [Ni(CN)₄]^2-,hybridised state of Ni=dsp² shape=Square planar

(c) According to Werner’s theory,

CoCl₃.6NH₃ → [Co(NH₃)₆]³⁺3Cl^-
CoCl₃.5NH₃ → [Co(NH₃)₅Cl]²⁺2Cl^-
CoCl₃.4NH₃ → [Co(NH₃)₄Cl₂]⁺Cl^-

When AgNO₃ in excess is treated with these complexes then following reactions takes place:-

[Co(NH₃)₆]³⁺3Cl^-+AgNO₃(Excess)→3AgCl+[Co(NH₃)₆]³⁺
[Co(NH₃)₅]²⁺2Cl^-+AgNO₃(Excess)→2AgCl+[Co(NH₃)₅]²⁺
[Co(NH₃)₄Cl₂]⁺Cl^-+AgNO₃(Excess)→AgCl+[Co(NH₃)₄ Cl₂]⁺

(b) Trans effect is the effect of a coordinated group upon the rate of substitution at the position trans to itself in a square or octahedral complex. As the rate of substitution of the trans ligand increases, the intensity of trans effect also increases. Thus, correct order is,

CN^- > C₆H₅^- > Br^- > NH₃

The Jahn-Teller effect is not observed in complexes with no degenerate energy levels. In high spin d8 complexes, the electronic configuration is t2g6 eg2, which has no degenerate energy levels, hence the Jahn-Teller effect is not observed.

(b) As negative charge on metal carbonyl complex increases, back p-bonding increases and hence bond length of C-O bond increases while bond length of metal-carbon bond decreases.

Hence, [Fe(CO)₄]^2- has longest C-O bond length among the given complexes.

The correct order of bond length of the given complexes is

${\left[\mathrm{Mn}{\left(\mathrm{CO}\right)}_6\right]}^{+} < \left[\mathrm{Ni}{\left(\mathrm{CO}\right)}_4\right] < {\left[\mathrm{Co}{\left(\mathrm{CO}\right)}_4\right]}^{-} < {\left[\mathrm{Fe}{\left(\mathrm{CO}\right)}_4\right]}^{2-}$