Chemistry

Chemical Bonding and Molecular Structure

1,277 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

TMS is the most suitable reference compound for NMR spectroscopy. However, it cannot be used with deuterium oxide solvent because:

  1. it is highly volatile
  2. it is chemically inert
  3. it is magnetically isotropic
  4. it is insoluble in deuterium oxide

  1. Only 1

  2. Only 2

  3. Only 2 and 3

  4. Only 3 and 4

  5. Only 4
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because chemical inertness, magnetically isotropic nature and high volatility of tetramethylsilane (TMS) makes is reference compound of choice for NMR studies. Because of its insolubility in deuterium oxide, it cannot be used with this solvent.

Multiple choice

Which of the following is the most reactive halogen?

  1. Fluorine

  2. Chlorine

  3. Bromine

  4. Iodine
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Fluorine is the most reactive halogen due to its small atomic size, high electronegativity (3.98 on the Pauling scale - the highest of all elements), and low F-F bond dissociation energy. Reactivity decreases down the group: F > Cl > Br > I. This extreme reactivity makes fluorine dangerous to handle and capable of reacting with almost any element, including noble gases under certain conditions.

Multiple choice

How many bonds carbon atom can form with other atoms?

  1. Nine

  2. Six

  3. Four

  4. Infinite
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A carbon atom has 4 valence electrons and forms 4 covalent bonds to achieve a stable octet configuration. This is called tetravalency and is why carbon can form countless organic compounds.

Multiple choice

Identify the false statement(s):

  1. B-F bond in BF4- is shorter than BF3 molecule.
  2. Sodium tetraborate decahydrate is used as an indicator.
  3. Borazine is isoelectronic with benzene and exhibits D3h symmetry.

  1. Only 1

  2. Only 2

  3. Only 3

  4. 1 and 2

  5. 2 and 3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  1. B-F bond is larger in BF4- than in BF3 molecule. This is due to the fact that in BF4-, the boron atom is sp3 hybridised while in BF3 the boron atom is sp2 hybridised and bond length decreases with increase in s-character as s-orbital is smaller than the p-orbital.
    1. Sodium tetraborate decahydrate or borax is not used as an indicator. Borax is used as a buffer because its aqueous solution contains equal amounts of weak acid and its salt.
    2. Borazine is isoelectronic with benzene and the symmetry point group in borazine is D3h. Hence, statements 1 and 2 both are false.
Multiple choice

Catenation means

  1. tendency to form chains

  2. tendency to form multiple bonds

  3. tendency to give protons

  4. tendency to get ionized
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ans : 1.