Hint: In order to solve this question, firstly we will apply the concept of bond energies of Carbon – Carbon bond, silicon direct bonding, direct bonding between Germanium atoms. Then we will compare all the given options to get the desired result.
Catenation is the joining into a series of atoms of the same element, called a chain. Carbon catenation occurs most readily, forming covalent bonds with other carbon atoms to form longer chains and structures. It is the reason why the overwhelming amount of organic compounds are found in nature.
A Carbon – Carbon bond is a covalent bond between two atoms. The single bond is the most common form: a bond composed of two electrons, one from each of the two atoms. The carbon-carbon single bond is a sigma bond, formed from each of the carbon atoms in one hybridized orbital.
The silicon direct bonding is based on intermolecular interactions including hydrogen bonds, strong covalent bonds. The initial direct bonding technique was characterized by a high-temperature operation.
The bonding between two Ge atoms in digermyne is different from carbon atoms in alkynes. Because of the multi bonded feature of digermynes and the large interatomic repulsion of two Ge atoms.
Central tendency decreases with the decrease in M-M bond energy.
Common bond energies (D) between C – C is 348KJ/mol.
Common bond energies (D) between Si – Si is 180KJ/mol.
Common bond energies (D) between Ge – Ge is 167KJ/mol.
So, the correct answer is “Option D”.
Note: While solving this question, we must know the difference between bond energy (D) i.e. It is defined as the amount of energy required to break apart a mole of molecules into its component atoms and bond lengths (r) i.e. It is defined as the average distance between nuclei of two bonded atoms in a molecule.