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 chemistry chemical bond and chemical equation coordinate bond types of bonds and properties chemical bonding and structure

What is a coordination compound?

  1. A metal atom or ion bonded by covalent bonds to ligands.

  2. Any atom bonded by ionic bonds to other atoms.

  3. Any atom bonded by covalent bonds to other atoms.

  4. A compound with covalent bonds.

  5. A metal atom bonded by ionic bonds to ligands.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A coordination compound is a metal atom or ion bonded by covalent bonds to ligands. For example, tetra carbonyl nickel $\displaystyle  Ni(CO) _4$ is a coordination compound with the metal atom ($Ni$ atom) which forms covalent bonds with $4$ $CO$ ligands.

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Which of the following molecule can combine with a proton $(H^{+})$?

  1. $NH _{3}$
  2. $Na^{+}$
  3. $HCl$
  4. $H _{3}O^{+}$
  5. $H$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The molecules already having positive charge $(Na^+ $ and $ H _3O^+) $ means that they are electron deficient and they can not combine with another proton $(H^+)$. $HCl$ is an acid, that releases a proton. Ammonia $NH _3$ acts as a base because, the unshared pair of electrons in the ammonia molecule can combine with a proton, forming the ammonium $(NH _4^+)$ ion. 

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Assertion: The weakest of the bonds between molecules are coordinate covalent bonds.
Reason: Coordinate covalent bonds represent the weak attractive force of the electrons of one molecule for the positively charged nucleus of another.

  1. <p>Both Assertion and Reason are correct and Reason is the correct explanation of Assertion</p>

  2. <p>Both Assertion and Reason are correct and Reason is not the correct explanation of Assertion</p>

  3. <p>Assertion is correct but Reason is not correct</p>

  4. <p>Assertion is not correct but Reason is correct</p>

  5. <p>Both the Assertion and Reason are not correct</p>
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Assertion: The weakest of the forces between molecules are dispersion forces or London forces.
Reason: Dispersion forces or London forces represent the weak attractive forces that originate as a result of instantaneous dipoles induced in atoms or molecules.
Hence, both the assertion and reason are not correct.

Multiple choice chemistry chemical bond and chemical equation coordinate bond types of bonds and properties chemical bonding and structure

Which of the following species cannot act as an electron pair donor for the formation of dative bond?

  1. H$ _3$I$^+$
  2. NH$ _4^+$
  3. OH$^-$
  4. NH$ _3$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In a dative bond, the shared pair of electrons come from the same atom. In $NH _{4}^{+}$ all the 4 valence electrons of N are bonded to the hydrogen atoms, thus it cannot act as an electron pair donor for the formation of dative bond.

Multiple choice chemistry chemical bond and chemical equation coordinate bond types of bonds and properties chemical bonding and structure

What is unique about the bonds in coordination compounds?

  1. One of the atoms or ions donates both shared electrons

  2. Both of the atoms or ions donate both shared electrons

  3. The metal is bonded to ligands

  4. The bond is a covalent bond

  5. The bond is an ionic bond
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The unique thing about the bonds in coordination compounds is that one of the atoms or ions donates both shared electrons. Thus, the bond is covalent coordinate bond.

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Dative bond is present in the molecule:

  1. ${NH} _{3}$
  2. ${CO} _{2}$
  3. $NaCl$
  4. $P{Cl} _{5}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Dative bond is present in the $\displaystyle PCl _5$ molecule.
In the solid state, $\displaystyle PCl _5$ molecule exists in the form of $\displaystyle [PCl _4]^+$ $\displaystyle [PCl _6]^-$
Dative bond is present in $\displaystyle [PCl _6]^-$ ion. The chloride ion is the donor atom and P atom is acceptor atom. The dative bond is also called co ordinate covalent bond.

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

A coordinate covalent bond is represented by an ______ from donor to acceptor.

  1. single arrow

  2. line

  3. double arrow

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

A coordinate covalent bond is represented by an single arrow from donor to acceptor.
A coordinate bond is formed when one atom donates its pair of electrons to the other atom. For example, a lone pair of electrons on N atom of ammonia is donated to a proton to form ammonium ion with a coordinate bond between N and H.

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Which of the following statements is/are true regarding $NH _4^+$?

  1. $NH _4^+$ contains a dative bond
  2. Bond angle increases when a bond is formed between $NH _3$ and $H^+$.
  3. $NH _4^+$ has pyramidal shape.
  4. The type of hybridisation changes when a bond is formed between $NH _3$ and $H^+$
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

 (A) $\displaystyle NH _4^+$ ion contains a dative bond (co-ordinate covalent bond) between $\displaystyle N$ atom and  $\displaystyle H$ atom.
$\displaystyle H _3N \rightarrow H^+$

(B) Bond angle increases when a bond is formed between $\displaystyle NH _3$ and $\displaystyle H^+$. In $\displaystyle NH _3$ molecule, due to repulsion between lone pair and bond pair of electrons, the bond angle decreases. When $\displaystyle NH _4^+$ ion is formed, lone pair is converted into bond pair. The inter electron repulsion decreases and bond angle increases.

(C) $\displaystyle NH _4^+$ ion has tetrahedral shape. $\displaystyle NH _3$ molecule has pyramidal shape.

(D) The type of hybridisation is not changed when bond is formed between $\displaystyle NH _3$ and $\displaystyle H^+$

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

The pair of compounds having coordinate covalent bonds is:

  1. $Br _{2}$ and $Hg$
  2. $Cl _{2}$ and $F _{2}$
  3. $NH _{4}^{+}$ and $H _{3}O^{+}$
  4. $Fe$ and $CO$

  5. Diamond and Graphite
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\displaystyle  NH^+ _4$  and $\displaystyle  H _3O^+$  have coordinate covalent bonds.
$\displaystyle  NH^+ _4$ is formed by a coordinate covalent bond between $\displaystyle  NH _3$  and $\displaystyle  H^+$.
$\displaystyle  H _3O^+$ is formed by a coordinate covalent bond between $\displaystyle  H _2O$  and $\displaystyle  H^+$. 

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Which of the following compounds contain a coordinate covalent bond?

  1. $Ba{Cl} _{2}$
  2. $CaCl$
  3. ${K} _{2}O$
  4. ${N} _{2}{H} _{3}^{+}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$\displaystyle {N} _{2}{H} _{3}^{+}$ contain a coordinate covalent bond.
$\displaystyle H-N=\underset{\displaystyle \underset{\displaystyle H}{\downarrow}}{N}^+-H$
The N atom is the donor atom and H atom is the acceptor atom.

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Which one of the following statements is true for ammonium ion?

  1. All bonds are ionic.

  2. All bonds are dative bonds.

  3. Hydrogen atoms are situated at the corners of a tetrahedron.

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

In $\displaystyle ammonium $ ion $\displaystyle NH _4^+$ three $\displaystyle N-H$ bonds are covalent and one $\displaystyle N-H$ bond is coordinate covalent (dative). $Hydrogen$ atoms are situated at the corners of a tetrahedron as $\displaystyle N$ atom is $\displaystyle sp^3$ hybridised.

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Coordinate bond is present in:

  1. Hydronium ion

  2. Water

  3. Sulphur dioxide

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


From the given compounds only Hydronium ion forms a coordinate or dative bond, where $O$ is the donor atom and $H$ is the acceptor.

Hydronium ion can be shown as:
$\displaystyle H _2O \rightarrow H^+$  or $\displaystyle H _3O^+$.
Hence, the correct option is A. 

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Coordinate bond is denoted and named respectively as:

  1. arrow, dative bond

  2. dots, dative bond

  3. arrow, covalency

  4. dots, hydrogen bond
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Coordinate covalent bond is a special type of covalent bond in which only one of the bonded atoms contributes the electron pair for sharing.

The coordinate covalent bond is denoted by an arrow and the arrow point towards the acceptor. The other name for it is the dative bond. 

For example, the coordinate covalent bond in $\displaystyle \displaystyle ammonia : boron : trifluoride$ is denoted by an arrow as $\displaystyle \displaystyle H _3N \rightarrow BF _3$.

Hence, the correct option is A.

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Which of the following molecules contains covalent and coordinate bonds?

  1. $CCl _4$
  2. $H _2SO _4$
  3. $NaCl$
  4. $Mg(OH) _2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Coordinate bond is formed between electron rich and electron deficient atoms. The donor atom should have at least one lone pair of electrons and the acceptor atom should have at least one vacant orbital.

In $NH _4^+$, the nitrogen in $NH _3$ is electron rich and $H^+$ ion do not contain any electron. Thus nitrogen from $NH _3$ share pair of electrons with $H^+$ to make a coordinate bonds.
Other bonds in $NH _3$ are covalent bonds.
$NH _3 + H^+ \rightarrow NH _4^+$