Which of the following molecules/ions does not contain unpaired electrons?

Among the following mixtures, dipole-dipole as the major interaction is present in

• benzene and ethanol

• acetonitrile and acetone

• KCl and water

• KCl and water

Which one of the following sets of ions represents a collection of isoelectronic species?

• K⁺ , Cl^– , Ca²⁺, Sc³⁺

• Ba^2+, Sr²⁺, K⁺ , S^2–

• N^3–, O^2–, F^– , S^2–

• N^3–, O^2–, F^– , S^2–

In which of the following molecules/ions are all the bonds not equal?

• SF₄

• SiF₄

• XeF₄

• XeF₄

Nickel (Z = 28) combines with a uninegative monodentate ligand X–
to form a paramagnetic complex [NiX₄ ]^{2 −}. The number of unpaired electron(s) in the nickel and geometry of this complex ion are,
respectively

• one, tetrahedral

• two, tetrahedral

• one, square planar

• one, square planar

In Fe(CO)_5, the Fe – C bond possesses 

•  π-character only

• both σ and π characters

• ionic character

• ionic character

The decreasing values of bond angles from NH3 (106^o ) to SbH₃ (101^o ) down group-15 of the periodic table is due to

• increasing bp-bp repulsion

• increasing p-orbital character in sp³

• decreasing lp-bp repulsion

• decreasing lp-bp repulsion

Which one of the following species is diamagnetic in nature?

• He₂⁺

• H₂

• H₂⁺

• H₂⁺

The number and type of bonds between two carbon atoms in calcium carbide are

• One sigma, one pi

•  One sigma, two pi

• Two sigma, one pi

• Two sigma, one pi

290.

Of the following sets which one does NOT contain isoelectronic species?

• PO^-3₄,SO₄^-2, ClO₄^-

• CN^-, N₂, C₂^-2

• SO₃^-2, CO₃^-2,NO₃^-

• SO₃^-2, CO₃^-2,NO₃^-