A Lewis base among the following is:

Which of the following pairs are isoelectronic and isostructural?

1. ${\mathrm{CO}}_3^{2-},$ ${\mathrm{NO}}_3^{-}$

2. ${\mathrm{ClO}}_3^{-},$ ${\mathrm{CO}}_3^{2-}$

3. ${\mathrm{SO}}_3^{2-},$ ${\mathrm{NO}}_3^{-}$

4. ${\mathrm{ClO}}_2^{-},$ ${\mathrm{SO}}_3^{2-}$

In context with beryllium, which one of the following statements is incorrect?

1. It is rendered passive by nitric acid
2. It forms ${\mathrm{Be}}_2\mathrm{C}$
3. Its salts rarely hydrolyze
4. Its hydride is electron-deficient and polymeric

Which of the following reactions does not exhibit the oxidising behaviour of H₂SO₄?

1. Cu + 2H₂SO₄ → CuSO₄ + SO₂ + 2H₂O

2. 3S + 2H₂SO₄ → 3SO₂ + 2H₂O

3. C + 2H₂SO₄ → CO₂ + 2SO₂ + 2H₂O

4. CaF₂ + H₂SO₄ → CaSO₄ + 2HF

A pair of d-orbitals having electron density along the axes is: 

1. $d_{z^2},$ $d_{xz}$

2. $d_{xz},$ $d_{zy}$

3. $d_{z^2},$ $d_{x^2-y^2}$

4. $d_{xy},$ $d_{x^2-y^2}$

The correct shape and hybridization for XeF₄ are:

1. Octahedral, sp³d²

2. Trigonal bipyramidal, sp³d³

3. Planar triangle, sp³d³

4. Square planar, sp³d²

Which of the following is the incorrect statement?

1. PH₅  and BiCl₅  do not exist

2. pπ - dπ bonds are present in SO₂

3. SeF₄ and CH₄  have the same shape

4. \(\mathrm{I_{3}^{+}}\) $\mathrm{has}$ $\mathrm{bent}$ $\mathrm{geometry}$

The correct increasing order of trans-effect of the following species is:

1.  ${\mathrm{NH}}_3>{\mathrm{CN}}^{-}>\mathrm{Br}>{\mathrm{C}}_6{\mathrm{H}}_5^{-}$

2.  ${\mathrm{CN}}^{-}>{\mathrm{C}}_6{\mathrm{H}}_5^{-}>{\mathrm{Br}}^{-}>{\mathrm{NH}}_3$

3.  ${\mathrm{Br}}^{-}>{\mathrm{CN}}^{-}>{\mathrm{NH}}_3>{\mathrm{C}}_6{{\mathrm{H}}^{-}}_5$

4.  ${\mathrm{CN}}^{-}>{\mathrm{Br}}^{-}>{\mathrm{C}}_6{{\mathrm{H}}^{-}}_5>{\mathrm{NH}}_3$

Identify the incorrect statements related to lanthanons:
 

Jahn-Teller effect is not observed in high spin complexes of?

1. d⁷

2. d⁸

3. d⁴

4. d⁹