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Question Bank No: 2

1. The number of antibonding electron pairs in $O_{2}^{2 -}$ ion on the basis of MO theory is

a)		4
b)		3
c)		2
d)		5

2. The calculated bond order in $H_{2}^{-}$ ion is

a)		0
b)		$\frac{1}{2}$
c)		$- \frac{1}{2}$
d)		1

3. BC $l_{3}$ molecule is planar while NC $l_{3}$ is pyramidal because

a)		BC $l_{3}$ does not have lone pair on B but NC $l_{3}$ has
b)		B-Cl bond is more polar than N-Cl bond
c)		N atom is smaller than B
d)		N - Cl bond is more covalent than B-Cl bond

4. Given electronic configuration of four elements as (1) 1 $s^{2}$ (11) 1 $s^{2}$ 2 $s^{2}$ 2 $p^{2}$ (111) 1 $s^{2}$ 2 $s^{2}$ 2 $p^{5}$ and (1V)1 $s^{2}$ 2 $s^{2}$ 2 $p^{6}$ .The one which is capable of forming ionic as well as covalent bond is

a)		1
b)		11
c)		111
d)		1V

5. The molecule of which of the following substance has ( $μ > 0$ )

a)		Water
b)		Methane
c)		Carbon dioxide
d)		Nitrogen

6. In the resonating structure of benzene, the number of $σ and π$ bonds are

a)		3 $π$ and 12 $σ$
b)		3 $σ$ and 12 $π$
c)		6 $π$ and 6 $σ$
d)		12 $π$ and 12 $σ$

7. Which of the following molecules is linear ?

a)		$C_{2} H_{2}$
b)		$C H_{4}$
c)		$H_{2} O$
d)		$N H_{3}$

8. Which of the following compounds shows ionic, covalent and co-ordinate bond as well?

a)		${CaSO}_{4} . {5 H}_{2} O$
b)		${CuSO}_{4} . {5 H}_{2} O$
c)		$HCl$
d)		$NaCl$

9. The correct order of bond angles in the molecules, $H_{2} O$ , ${NH}_{3}$ , ${CH}_{4}$ and ${CO}_{2}$ is

a)		$H_{2} O < {NH}_{3} < {CO}_{2} < {CH}_{4}$
b)		$H_{2} O < {NH}_{3} > {CO}_{2} > {CH}_{4}$
c)		$H_{2} O > {NH}_{3} < {CH}_{4} > {CO}_{2}$
d)		${CO}_{2} > {CH}_{4} > {NH}_{3} >$ $H_{2} O$

10. Antibonding MO is formed by

a)		Addition of atomic orbitals
b)		substraction of atomic orbitals
c)		multiplication of atomic orbitals
d)		none of these

11. Most efficient overlapping is

a)		${sp}^{2} - {sp}^{2}$
b)		$s - s$
c)		${sp}^{3} - {sp}^{3}$
d)		$sp - sp$

12. Among the following the electron deficient compound is

a)		${CCl}_{4}$
b)		${PCl}_{5}$
c)		${BeCl}_{2}$
d)		${BCl}_{3}$

13. The high density of water compared to ice is due to

a)		dipole-dipole interactions
b)		hydrogen bonding interaction
c)		dipole induced dipole interaction
d)		none of the above

14. The molecular species having highest bond order is

a)		$O_{2}$
b)		${O_{2}}^{-}$
c)		${O_{2}}^{+}$
d)		$O_{2}^{2 -}$

15. Which one of these is weakest?

a)		ionic bond
b)		covalent bond
c)		metallic bond
d)		van der Waal's forces

16. Other factors being constant which bond order is expected to correspond to shortest bond length

a)		$2 \frac{1}{2}$
b)		$1 \frac{1}{2}$
c)		$2$
d)		$0.5$

17. The correct order of decreasing polarisability of the ions is

a)		${Cl}^{-}$ , ${Br}^{-}$ , $I^{-}$ , $F^{-}$
b)		$F^{-}$ , $I^{-}$ , ${Br}^{-}$ , ${Cl}^{-}$
c)		$F^{-}$ , ${Cl}^{-}$ , ${Br}^{-}$ , $I^{-}$
d)		$I^{-}$ , ${Br}^{-}$ , ${Cl}^{-}$ , $F^{-}$

18. The maximum extent of H- bonding is shown by

a)		$H_{2} O$
b)		$H_{2} Se$
c)		$H_{2} S$
d)		$HF$

19. According to MOT, the species ${O_{2}}^{+}$ possesses

a)		bond order of 2.5
b)		three unpaired electrons
c)		diagmagnetic character
d)		stability lower than $O_{2}$

20. Which of the following does not apply to bonding in metals?

a)		nondirectional bonds
b)		mobility of valence electrons
c)		delocalisation of electrons
d)		Highly directed bonds

21. Sulphuric acid molecule contains

a)		only covalent bonds
b)		covalent and ionic bonds
c)		covalent and co-ordinate bonds
d)		covalent, ionic and co-ordinate bonds

22. The internuclear distance in $H_{2}$ and ${Cl}_{2}$ molecules are 74 and 198 pm respectively. The bond length of HCl is

a)		272 pm
b)		124 pm
c)		136 pm
d)		248 pm

23. Beryllium atom in beryllium fluoride is

a)		${sp}^{3}$ hybridised
b)		${sp}^{2}$ hybridised
c)		$sp$ hybridised
d)		unhybridised

24. A ${sp}^{3}$ hybrid orbital contains

a)		1/4 s- character
b)		1/2 s- character
c)		2/3 s- character
d)		3/2 s- character

25. A bond with maximum covalent character between non-metallic elements is found

a)		Between atoms of same size
b)		Between chemically similar atoms
c)		Between identical atoms
d)		Between atoms of widely differing electronegativities

26. The molecule which has the largest dipole moment amongst the following is

a)		${CH}_{4}$
b)		${CHCl}_{3}$
c)		${CCl}_{4}$
d)		${CHl}_{3}$

27. In ${CCl}_{4}$ , the four valencies of carbon are directed towards the corners of a

a)		Cube
b)		Hexagon
c)		Prism
d)		Tetrahedron

28. Which of the following bonds has the most polar character?

a)		$C - O$
b)		$C - Br$
c)		$C - F$
d)		$C - S$

29. In which of the following the angle between the two covalent bonds is largest?

a)		$H_{2} O$
b)		${NH}_{3}$
c)		${CO}_{2}$
d)		${CH}_{4}$

30. The molecules ${BF}_{3}$ and ${NF}_{3}$ both are covalent compounds. But ${BF}_{3}$ is non- polar and ${NF}_{3}$ is polar. The reason is that

a)		Boron is a metal and nitrogen is a gas in uncombined state
b)		BF bonds have no dipole moment whereas NF bonds have dipole moment
c)		Atomic size of boron is smaller than that of nitrogen
d)		${BF}_{3}$ is planar but ${NF}_{3}$ is pyramidal in shape

31. Covalent compounds are soluble in

a)		Polar solvents
b)		Non-polar solvents
c)		Concentrated acids
d)		All solvents

32. In which of the compound, there is an electrovalent linkage

a)		$O_{2}$
b)		${CCl}_{4}$
c)		${CHCl}_{3}$
d)		$NaBr$

33. Element X is strongly electropositive and element Y is strongly electronegative. Both are univalent. The compound formed would be

a)		$X^{+} Y^{-}$
b)		$X^{-} Y^{+}$
c)		$X - Y$
d)		$X \to Y$

34. Among the 2nd group elements, the metal forming predominently covalent compound is

a)		Be
b)		Mg
c)		Sr
d)		Ca

35. Which of the following bonds has most polar character?

a)		C-O
b)		C-Br
c)		C-F
d)		C-S

36. Which of the following does not apply to bonding in metals

a)		Non directional bonds
b)		Mobility of valence electrons
c)		Delocalisation of electrons
d)		Highly directed bonds