Bond Energy

Bond Energy MDCAT MCQs with answers

15 past paper MCQs on Bond Energy, from the Chemical Bonding unit of MDCAT Chemistry. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.

Read the notes first Practise the unit as a quiz

1.Which of the following halogen molecules has the maximum bond energy? (MDCAT 2020)

  1. $\mathrm{F_2}$
  2. $\mathrm{Cl_2}$
  3. $\mathrm{Br_2}$
  4. $\mathrm{I_2}$
Show answer

Correct answer: (b) $\mathrm{Cl_2}$

Chlorine is the strongest of the halogen bonds; in $\mathrm{F_2}$ the two small atoms' lone pairs repel and weaken it.

2.What is the reason for energy changes in chemical reactions? (MDCAT 2023)

  1. ionic bonds
  2. bond breakage only
  3. bond formation and breakage
  4. hydrogen bonding
Show answer

Correct answer: (c) bond formation and breakage

Breaking bonds absorbs energy and forming them releases it, and the balance of the two is the enthalpy change.

3.The bond energy of hydrogen in the $\mathrm{H_2}$ molecule is: (MDCAT 2023)

  1. $242\ \mathrm{kJ\,mol^{-1}}$
  2. $431\ \mathrm{kJ\,mol^{-1}}$
  3. $436\ \mathrm{kJ\,mol^{-1}}$
  4. $346\ \mathrm{kJ\,mol^{-1}}$
Show answer

Correct answer: (c) $436\ \mathrm{kJ\,mol^{-1}}$

It takes $436\ \mathrm{kJ\,mol^{-1}}$ to break the H-H bond.

4.Which of the following has highest bond energy? (KMU MDCAT 2025)

  1. HCl
  2. HI
  3. HF
  4. HBr
Show answer

Correct answer: (c) HF

The bond is shortest and strongest to the smallest halogen, so it is highest in hydrogen fluoride.

5.Correct order of bond energy will be: (SIBA MDCAT 2025)

  1. HCl>HBr>HI
  2. HBr>HCl>HI
  3. HI>HCl>HBr
  4. HCl>HI>HBr
Show answer

Correct answer: (a) HCl>HBr>HI

The bond shortens as the halogen gets smaller, so it is strongest in hydrogen chloride of these three.

6.Predict the highest bond energy of the following single bond: (NUMS MDCAT 2024)

  1. C-H
  2. C-N
  3. C-O
  4. C-C
Show answer

Correct answer: (a) C-H

The bond to the small hydrogen atom is the shortest and strongest of the four.

7.Identify the following compound having shortest bond length: (NUMS MDCAT 2024)

  1. Methyl amine
  2. Formamide
  3. Formic acid
  4. Ethanol
Show answer

Correct answer: (c) Formic acid

The carbon oxygen double bond of the carboxyl group is the shortest bond among these.

8.The factor which is not affecting bond length is: (NUMS MDCAT 2023)

  1. Pressure of multiple bonds
  2. Nature of hybridization present
  3. Difference in electronegativity between the two bonded atoms
  4. Ionization energies of the two bonded atoms
Show answer

Correct answer: (d) Ionization energies of the two bonded atoms

Bond length turns on the size of the atoms, the bond order and the hybridization, not on ionization energy.

9.The bond energy of hydrogen in H2 molecule is: (UHS MDCAT 2023)

  1. 242 KJ/mol
  2. 431 KJ/mol
  3. 436 KJ/mol
  4. 346 KJ/mol
Show answer

Correct answer: (c) 436 KJ/mol

The bond in hydrogen takes $436\,\mathrm{kJ\,mol^{-1}}$ to break.

10.If bond energy of C-CI is 346 kJ/mol. The bond enegy of C-Br should be: (PMC MDCAT 2022)

  1. 290 kJ/mol
  2. 390 kJ/mol
  3. 490 kJ/mol
  4. 590 KJ/mol
Show answer

Correct answer: (a) 290 kJ/mol

Bromine is the larger atom, so its bond to carbon is longer and weaker.

11.The amount of energy required to beak one mole of a particular type of bond is equal to its: (PMC MDCAT 2022)

  1. Activation energy
  2. Ionization energy
  3. Bond Energy
  4. Potential energy
Show answer

Correct answer: (c) Bond Energy

That energy is the bond energy.

12.Which of these has a bond length of ______ 174 pm? (PMC MDCAT 2022)

  1. C-C
  2. Cl-Cl
  3. Cl-H
  4. C-Cl
Show answer

Correct answer: (d) C-Cl

The carbon chlorine bond is about $174\,\mathrm{pm}$, the sum of the two covalent radii.

13.When repulsive forces tend to push the atoms apart and the potential energy of the system is_______ (PMC MDCAT 2022)

  1. No Effect
  2. Decrease
  3. Increase
  4. Change in alternation
Show answer

Correct answer: (c) Increase

Pushed closer than the bond length, the atoms repel and the energy of the system climbs steeply.

14.When two atoms are bonded to form a stable compound, the attractive forces will ______ repulsive forces and the potential energy of the system will be _______. (PMC Practice 2021)

  1. Recessive, higher
  2. Dominate, minimum
  3. Dominate, maximum
  4. Recessive, lower
Show answer

Correct answer: (b) Dominate, minimum

A bond forms where the attraction wins and the energy of the pair is at its lowest.

15.The average bond energy of C-Br is (UHS MDCAT 2016)

  1. 228 kJmol-1
  2. 200 kJmol-1
  3. 250 kJmol-1
  4. 290 kJmol-1
Show answer

Correct answer: (d) 290 kJmol-1

The carbon bromine bond energy is about $290\,\mathrm{kJ\,mol^{-1}}$.

More in Chemical Bonding