O-O single bond is weaker than S-S bond due to smaller size of O as compared to S. As a result, the lone pair of electrons on the both the O atoms repel each other leading to instability or weakening of O-O bond.

Breaking and making bonds Energy is absorbed to break bonds. Bond-breaking is an endothermic process. Energy is released when new bonds form. Bond-making is an exothermic process.

Kinetic energy, the energy of matter in motion, fuels the collisions of atoms, ions, and molecules that are necessary if their old bonds are to break and new ones to form. All molecules store potential energy, which is released when their bonds are broken.

(a) O has smaller size than S due to which the O-O bond length is short which results in repulsion of lone pairs on O making it unstable and the bond can be cleaved. Whereas due to big size of S, no such repulsion is present and the S-S bond is stronger than that between O-O.

Answer and Explanation: The main reason that oxygen-oxygen is a weak bond is that oxygen bond is so unstable. The another reason is that repulsion between two electron rich cloud on oxygen atoms. This causes repulsion among each other and therefore a weaker bond is formed.

Attraction of electrons towards each other: More the electrons are attracted, stronger is the bond formed. Hence, the strongest bond is the Cl-Cl bond. Therefore, the correct answer is option C.

F2 is more reactive than Cl2 due to greater repulsion in the non-bonded electron pairs in the molecule of F2 as compared to Cl2 therefore the bond cleavage in fluorine becomes easier.

Toluene has the lowest C – H bond dissociation energy compare to other three.

The bond energy is, thus, 99 kcal/mol, or 414 kJ/mol (the average of the bond-dissociation energies). None of the individual bond-dissociation energies equals the bond energy of 99 kcal/mol.

The bond dissociation energy of C2(599kJmol−1) decreases slightly on forming C2+(513kJmol−1) increases greatly on forming C2−(818kJmol−1).

These bond energies or bond dissociation enthalpies are always positive, since they represent the endothermic homolysis of a covalent bond.

Dissociation of course requires energy. But bond formation between ions and solvent molecules release energy.