Chemistry

Chemical Bonding and Molecular Structure

1,420 Questions

This section tests your knowledge of chemical bonding, molecular structure, and hybridization. It covers ionic and covalent bonds, octet rule exceptions, and molecular geometry. These chemistry questions are common in various competitive entrance examinations.

Ionic and covalent bondsHybridisation of elementsOctet rule exceptionsMolecular geometryIntermolecular forces

Chemical Bonding and Molecular Structure Questions

Multiple choice

Which of the following does not has a linear arrangement of atom?

  1. CO2

  2. C2H2

  3. BeH2

  4. H2O
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The oxygen has 6 valence electrons and thus needs 2 more electrons from 2 hydrogen atoms to complete its octet. Then, this leaves two lone electron pairs that are not bonded to any other atom. The two hydrogen atoms and the two lone electron pairs are as far apart as possible at nearly 109o bond angle. This is tetrahedral electron pair geometry. The two lone electron pairs exert a little extra repulsion on the two bonding hydrogen atoms to create a slight compression to a 104o bond angle. The water molecule is in bent molecular geometry because of the lone pairs of electrons.

Multiple choice

Which of the following bond(s) is/are present in ammonium chloride?

  1. Only ionic

  2. Only covalent

  3. Covalent and ionic

  4. Ionic, covalent and co-ordinate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

There is no covalent interaction between ammonium and chloride ions in the solid state. The ions are arranged in a cesium chloride structure having large cations and smaller anions in the ratio 1:1. However, bonding between nitrogen and the four hydrogens within the ammonium ion itself is covalent. 

Multiple choice

Which of the following has the strongest bond?

  1. C-C

  2. C=C

  3. C≡C

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Triple bond on the other hand adds another pi orbital to the existing sigma and pi orbitals making the triple bond stronger than the previous two and also shorter. The order of strength of bonds is C≡C > C=C > C-C.

Multiple choice

Which of the following is not a planar molecule?

  1. BCl3

  2. C2H4

  3. XeF<sub style="color:">4

  4. PCl<sub style="color:">3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

PCl3 has sp3 hybridisation. Due to the presence of three bonding pairs and one lone pair, the resulting geometry is pyramidal.

Multiple choice

Which of the following has the highest bond angle?

  1. <span style="font-family:" arial;="" font-size:="" 12pt;="" mso-fareast-font-family:="" times;="" new="">H2O

  2. <span style="font-family:" arial;="" font-size:="" 12pt;="" mso-fareast-font-family:="" times;="" new="">CO2

  3. <span style="font-family:" arial;="" font-size:="" 12pt;="" mso-fareast-font-family:="" times;="" new="">CH4

  4. <span style="font-family:" arial;="" font-size:="" 12pt;="" mso-fareast-font-family:="" times;="" new="">NH3
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

CO2 has linear geometry with bond angle 180°. This is the highest bond angle among the given molecules.

Multiple choice

Directions: The following question has four choices out of which ONLY ONE is correct.

Which of the following has the strongest covalent bond?

  1. H-Cl

  2. Cl-Cl

  3. C-Cl

  4. Na-Cl
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Covalent bonds are affected by the electronegativity of the connected atoms. Two atoms with equal electronegativities will make non-polar covalent bonds such as Cl−Cl. An unequal relationship creates a polar covalent bond such as with H−Cl.

Multiple choice

Which of the following matches is correct?

  1. Dipole moment: CO2<NH3<NF3<H2O

  2. Bond strength: N2<O2<I2<H2

  3. Ionic character: CaF2<CaCl2<CaBr2<CaI2

  4. Boiling point: PH3<AsH3<NH3<SbH3

  5. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Unlike expected order of boiling point, i.e., NH3<PH3<AsH3 <SbH3, the actual order of boiling points is PH3<AsH3<NH3<SbH3.  Boiling point of NH3 is exceptionally high due to the presence of H-bonding.

Multiple choice

In which of the following ionization processes, the magnetic behaviour has changed and the bond order has increased?

  1. N2→ N2+

  2. O2→ O2+

  3. F2→ F2-

  4. C2→C2+

  5. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

O2 (16 e-) : ϭ1s2 ϭ*1s2 ϭ2s2 ϭ*2s2 ϭ2pz2 π2px2 π2py2 ϭ*2pz2 Bond order  = ½ (6-2) = 2, diamagnetic

O2+ (15 e-) : ϭ1s2 ϭ*1s2 ϭ2s2 ϭ*2s2 ϭ2pz2 π2px2 π2py2 ϭ*2pz1 Bond order  = ½ (6-1) = 2.5, paramagnetic

Magnetic behaviour changes from diamagnetic to paramagnetic; Bond order increased

Multiple choice

Which of the following statements is true?

  1. Ionic bond is non-directional.

  2. Ionic compounds do not conduct electricity in their molten state.

  3. Ionic compounds are highly soluble in non-polar solvents.

  4. The rates of ionic reactions are very slow.

  5. Ionic compounds have very low high melting and boiling points.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 Ionic bond is directionless (non-directional), and the electrostatic forces of attraction are present in all directions around an ion.