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

Assertion: Ammonia forms the complex ion [Cu(NH3)4]+2 with copper ions in alkaline solution but not in acidic solution. Reason: In acidic solution, hydration protects copper ions.

  1. Both A and R is true and R is the correct explanation of A.

  2. Both A and R is true but R is not the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R is false.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In acidic solution, NH3 forms a bond with H+ to give NH4+ ion which do not have a lone pair on N to act as a ligand because this ammonia forms the complex ion [Cu(NH3)4]+2 with copper ions in alkaline solution but not in acidic solution, so this option is correct.

Multiple choice

Assertion: Glycinate ion is an example of monodentate ligand. Reason: It contains N as the only donor atom.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is not the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Both A and R are false because glycinate ion is a bidentate ligand and it contains N and O as donor atom.

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.