CBSE Class 10 Answered

sp Hybridisation

• Intermixing of one 's' and one 'p' orbital of almost equal energy to give two identical and degenerate hybrid orbitals is called 'sp' hybridisation.
• These sp-hybrid orbitals are arranged linearly by making a 180° angle.
• They possess 50% 's' and 50% 'p' character.

Structure of C₂H₂:

• The ground state configuration of ‘C’ being 1s² 2s² 2p_x¹ 2p_y¹ has only two unassociated electrons. Carbon makes four bonds because its valency is four.
• For this, 4 unpaired electrons are required. Hence, it promotes its 2s electron to the empty 2p_z orbital in the excited state.
• So, the excited state electronic configuration of carbon is 1s² 2s¹ 2p_x¹ 2p_y¹ 2p_z¹. Each carbon atom undergoes ‘sp’ hybridisation by using 2s and 2p orbitals in the excited state to give two half-filled ‘sp’ orbitals, which are arranged linearly.