Question

Which one is the strongest bond?
(A) $Br-F$
(B) $F-F$
(C) $Cl-F$
(D) $Br-Cl$

Answer 1

Hint: Chemical bonds are formed by the sharing, or transfer of electrons between two atoms. Bond energy is the amount of energy that was needed to break the bond. Higher the bond energy stronger will be the bond. Bond energy depends on electronegativities and electronic repulsions.

Complete answer:
Chemical bonds are of different types. When an electron is transferred from one atom to another atom, it leads to the formation of ionic bonds. When two electrons are shared between two atoms, then the covalent bond will be formed.
Covalent bond is formed between the atoms with similar electronegativities.
Given atoms are halogens, which are mostly non-metallic and have high electronegativity values.
Bond energy is one of the useful concepts that decides the strength of the chemical bond present between the two atoms.
More will be the bond energy; more will be the strength of the bond.
The bond-energy of $Br-F$ is $237kJ{\left(mol\right)}^{-1}$
The bond energy of $F-F$ is $154kJ{\left(mol\right)}^{-1}$
The bond energy of $Cl-F$ is $253kJ{\left(mol\right)}^{-1}$
The bond energy of $Br-Cl$ is $218kJ{\left(mol\right)}^{-1}$
From the above values of bond energy, the chlorine-fluorine bond is the strongest bond.
Thus, $Cl-F$ is the strongest bond.

Note:
The bond energy depends upon the values of electronegativity and electron repulsions. Generally, electronegativity is directly proportional to bond energy, in that case $F-F$ bond should be the strongest bond. But due to the small size of fluorine atoms, $F-F$ bond has high electron repulsions which leads to weaker bonds which leads to $Cl-F$ as the strongest bond.