PPSC Lecturer Chemistry Past Paper Dated: 2015 41- The chemical which destroys the ozone layer is: A. N₂OB. CH₄C. CO₂D. CFCl₃ View Answer Answer : D. CFCl₃ Description 42- Physisorption occurs at: A. Any temperatureB. Room temperatureC. High temperatureD. Low temperature View Answer Answer : D. Low temperature Description 43- If the dispersion medium is gas, the example is: A. AerosolB. FoamC. EmulsionD. Gel View Answer Answer : A. Aerosol Description 44- Pressure vs temperature equation is called: A. Langmuir equationB. Freundlich equationC. BET equationD. Gay-Lussac’s Law View Answer Answer : D. Gay-Lussac's Law Description 45- Resonating structures cannot be: A. DrawnB. SeparatedC. IdentifiedD. Stabilized View Answer Answer : B. Separated Description 46- Nickel is used in the hydrogenation of: A. RubberB. CoalC. Vegetable gheeD. Petroleum View Answer Answer : C. Vegetable ghee Description 47- Colloids show: A. Brownian movementB. Tyndall effectC. Both A and BD. None of these View Answer Answer : A. Brownian movement Description 48- The methyl group is ortho and para directing because of: A. Electron-donating effect inductivelyB. Electron-donating effect resonatinglyC. Electron-donating effect by hyperconjugationD. All of the above View Answer Answer : D. All of the above Description 49- The chloro group is ortho/para directing but: A. Electron withdrawingB. Electron donatingC. NeutralD. None of these View Answer Answer : A. Electron withdrawing Description 50- To avoid maximum yield for a reversible reaction, use: A. Glass vesselB. Closed vesselC. Open vesselD. Copper vessel View Answer Answer : B. Closed vessel Description 51- In benzene, there are _______ type(s) of carbon atoms. A. One typeB. Two typesC. Three typesD. Four types View Answer Answer : A. One type Description 52- In benzene, the number of pi electrons is: A. 3 electronsB. 4 electronsC. 6 electronsD. 8 electrons View Answer Answer : C. 6 electrons Description 53- In benzene, all carbon atoms are _______ hybridized. A. sp³B. sp²C. spD. sp³d View Answer Answer : B. sp² Description 54- According to Le Châtelier's principle, in a reversible reaction between solid and liquid, the amount of heat added: A. Depends on the reactionB. Decreases the concentration of liquidC. Increases the concentration of solidD. Decreases the concentration of solid View Answer Answer : A. Depends on the reaction Description 55- The fastest reaction occurs in which of the following? A. Rusting of ironB. Burning of coalC. AgCl formation by reaction of AgNO₃ and NaClD. Photosynthesis View Answer Answer : C. AgCl formation by reaction of AgNO₃ and NaCl Description 56- The amount of energy required to separate nucleons is called: A. Ionization energyB. Binding energyC. Lattice energyD. Activation energy View Answer Answer : B. Binding energy Description 57- The enthalpy of heat of formation of a sodium ion from its atom is known as: A. Enthalpy of formationB. Enthalpy of combustionC. Enthalpy of atomizationD. First ionization energy View Answer Answer : D. First ionization energy Description 58- The brown vapor is formed of which element when MnO₂ and conc. H₂SO₄ are added? A. I₂B. Br₂C. Cl₂D. NO₂ View Answer Answer : D. NO₂ Description 59- Stability of the nucleus is due to: A. Protons and neutronsB. Protons and electronsC. Neutrons and electronsD. Only protons View Answer Answer : A. Protons and neutrons Description 60- The difference between particle mass and actual mass is called: A. Isotopic massB. Atomic massC. Mass numberD. Mass defect View Answer Answer : D. Mass defect Description 1 2 3 4 5
