General
✓✗In which of the following does the hybridisation of the central atom change on going from the first species to the second?
- BF3 → BF4−
- H2O → H3O+
- CH4 → CCl4
- NH3 → NH4+
General
✓✗During the change of O2 to O2−, the added electron goes into which one of the following orbitals?
- σ orbital
- σ* orbital
- π orbital
- π* orbital
General
✓✗Consider the C−H bonds marked in the following compounds: I. a C−H bond of benzene; II. the terminal ≡C−H bond of phenylacetylene (C6H5C≡C−H); III. a C−H bond of cyclopropane. The correct order of the bond dissociation energy of these C−H bonds is
- I > II > III
- II > III > I
- II > I > III
- III > II > I
General
✓✗Which of the following species has a bond order of 3?
- NO
- O2+
- N2−
- NO+
General
✓✗Which of the following molecules is non-polar?
- NH3
- CO2
- HCl
- H2O
General
✓✗The correct order of the bond angle at oxygen in Cl2O, H2O and OF2 is
- H2O > OF2 > Cl2O
- OF2 > H2O > Cl2O
- H2O > Cl2O > OF2
- Cl2O > H2O > OF2
General
✓✗The number of 90° F−S−F angles in SF6 is
- 12
- 8
- 4
- 6
General
✓✗The bond angle in OF2 (about 103°) is slightly smaller than that in H2O (104.5°) because
- F is less electronegative than H
- the electronegative F atoms pull the bond pairs away from O, reducing bond pair repulsion
- OF2 is linear
- O in OF2 has fewer lone pairs
General
✓✗The formal charge on an atom in a Lewis structure is calculated as
- valence electrons + non-bonding electrons
- bonding electrons − non-bonding electrons
- atomic number − valence electrons
- valence electrons − non-bonding electrons − (bonding electrons/2)
General
✓✗Consider the species CN+, CN−, NO and CN. Which one of these has the highest bond order?
- CN+
- CN
- NO
- CN−
General
✓✗As the bond order increases, the bond enthalpy
- remains the same
- decreases
- increases
- becomes zero
General
✓✗The decreasing order of stability of O2, O2−, O2+ and O22− is
- O22− > O2− > O2 > O2+
- O2+ > O2 > O2− > O22−
- O2 > O2+ > O22− > O2−
- O2− > O22− > O2+ > O2
General
✓✗Which pair has the same bond order and the same magnetic behaviour?
- NO and CO
- O2 and N2
- B2 and C2
- O22− and F2
General
✓✗The overlap of two s orbitals gives a
- hydrogen bond
- δ bond
- π bond
- σ bond
General
✓✗The hybridisation of the central carbon in allene (CH2=C=CH2) is
- sp
- dsp2
- sp2
- sp3