The strength of covalent bonds is influenced by the type of overlap between atomic orbitals. A double bond, having both a sigma and a pi bond, is stronger than a single bond due to the increased overlap. Here option A is correct.
Bond Strength: The strength of a covalent bond depends on the overlap of the atomic orbitals of the bonded atoms. The greater the overlap, the stronger the bond.
Double Bond: A double bond consists of one sigma bond and one pi bond. A sigma bond is formed by the end-to-end overlap of orbitals, while a pi bond is formed by the side-by-side overlap of orbitals. A pi bond has less overlap than a sigma bond, so it is weaker. However, a double bond is stronger than a single bond because it has both a sigma and a pi bond.
Single Bond: A single bond consists of only one sigma bond. It has less overlap and less strength than a double bond. Here option A is correct.
Complete question:
Which of the following correctly compares the strength of the two carbon-to-carbon bonds in the molecule represented in the Lewis diagram shown above?
A. The carbon-to-carbon bond on the left is stronger because it is a double bond.
B. The carbon-to-carbon bonds are the same strength because the C-C-CC-C-C bond angle is 180°180°.
C. The carbon-to-carbon bonds are the same strength because they are both bonds between carbon atoms.
D. The carbon-to-carbon bond on the right is stronger because there are more hydrogen atoms attached to the rightmost carbon atom than to the leftmost carbon atom.