The helical structure of protein is stabilized by

• dipeptide bond

• hydrogen bonds

• ether bonds

• peptide bonds

The dipole moment of HBr is 1.6 × 10^-30 cm and inter-atomic spacing is 1 Å. The % ionic character of HBr is

• 7

• 10

• 15

• 27

The C-O-H bond angle in ethanol is nearly

• 90°

• 104°

• 120°

• 180°

The molecule having zero dipole moment is

• CH₂Cl₂

• BF₃

• NF₃

• ClF₃

The bond angle is smallest in

• H₂O

• H₂S

• BeCl₂

• N₂O

Which of the following shell, form an outer octahedral complex?

• d⁴

• d⁸

• d⁶

• None of these

Valence bond theory of metallic bond was given by

• Dalton

• Drudel

• Fajan

• Pauling 

The calculated bond order in O${}_2^{-}$ ions is

• 1

• 1.5

• 2

• 2.5

329.

Which combination of atoms can form a polar covalent bond ?

• H and N

• H and Br

• N and N

• Na and Br

The bond length of H${}_2^{+}$, H${}_2^{-}$ and H₂ are in the following order

• H${}_2^{+}$ > H₂ > H${}_2^{-}$

• H₂ > ${\text{H}}_2^{+} > {\mathrm{H}}_2^{-}$

• H${}_2^{-}$ > H₂ > H${}_2^{+}$

• ${\mathrm{H}}_2^{-} > {\mathrm{H}}_2^{+}$ > H₂