Question

explain the bond formation in ethylene and acetylene​

Answer 1

Answer:

ethene consists of two sp​2-hybridized carbon atoms, which are sigma bonded to each other and to two hydrogen atoms each. The remaining unhybridized p orbitals on the carbon form a pi bond, which gives ethene its reactivity

Answer 2

Answer:

Bonding in Ethylene. C2H4:

(i) onding in ethylene can be explained by hybridisation concept.

(ii) The valency of carbon is 4. The electronic configuration of carbon is ls2 2s2 2p1x 2p1y 2p0z. One electron from 2s orbital is promoted to 2pz orbital in the excited state to satisfy the valency of carbon.

(iii) In ethylene both the carbon atoms undergo sp2 hybridisation involving 2s,2pxand2py orbitals resulting in 3 equivalent sp2 hybridised orbitals lying in the XY plane at an angle of 120∘ other. The unhybridised 2pz orbital lies perpendicular to the xy plane.

(iv) One of the sp2 hybridised orbitals of each carbon atoms lying along the X-axis linearly overlaps with each other resulting in the formation of C- C sigma bond. The other two sp2 hybridised orbitals of both carbon atom linearly overlap with the four Is orbitals of four hydrogen atoms leading to the formation of two C-H sigma bonds on each carbon atom.

(v) The unhybridised 2pz orbital of both carbon atoms can overlap only sideways as they are not in the molecular axis. This lateral overlap results in the formation of a pi bond between the two carbon atoms.

Bonding in acetylene (C2H2):

(i) The electronic configuration of valence shell of carbon atom in the ground state is [He]2s2 2p1x 2p0z. One electron from 2s orbital is promoted to 2pz orbital in the excited state to satisfy the valency of carbon.

(ii) n acetylene molecule, both the carbon atoms are in sp hybridised state. I he 2s and 2px Orbilals resulting in two equivalent sp hybridised orbitals are formed lying in a straigh: line along the X-axis. The unhybridised 2pyand2pz orbitals lie perpendicular to the X-axis.

(iii) One of the two sp hybridised orbitals of each carbon atom linearly overlaps with each other resulting in the formation of a C-C sigma bond. The other sp hybridised orbital of both carbon atoms linearly overlap with the two Is orbitals of two hydrogen atoms leading to the formation of one C-H sigma bond on each carbon atom.

(iv) The unhybridised 2pyand2pz orbitals of each carbon atom overlap sideways. This lateral overlap results in the formation of two pi bonds. (py−py)and(pz−pz) between the two carbon atoms.

Explanation: