9. For diatomic molecules, the correct statement(s) about the molecular orbitals formed by the overlap of two 2pz orbitals is (are) (A) orbital has a total of two nodal planes. (B) * orbital has one node in the xz-plane containing the molecular axis. (C) orbital has one node in the plane which is perpendicular to the molecular axis and goes through the center of the molecule. (D) * orbital has one node in the xy-plane containing the molecular axis. 10. The correct option(s) related to adsorption processes is (are) (A) Chemisorption results in a unimolecular layer. (B) The enthalpy change during physisorption is in the range of (C) Chemisorption is an endothermic process. BY (D) Lowering the temperature favours physisorption processes. O to 140 kJ mol-1. 11. The electrochemical extraction of aluminium from bauxite ore involves (A) the reaction of Al2O3 with coke (C) at a temperature > 2500C. (B) the neutralization of aluminate solution by passing CO2 gas to precipitate hydrated alumina (Al2O3.3H2O). (C) the dissolution of Al2O3 in hot aqueous NaOH. (D) the electrolysis of Al2O3 mixed with NaAIF6 to give Al and CO2.