Punjab Public Service Commission Lahore Lecturer Chemistry Sample Model Previous Papers
Preparation from Important Past MCQs Papers for more chemistry mcqs
1) When an electron is brought from infinite distance close to the nucleus of the atom, the energy of
(a) increases to a smaller negative value (b) decreases to a greater negative value
(c) decreases to a smaller positive value (d) increases to a greater positive value
2) The probability of finding the electron in the nucleus is:
(a) 100% due to forces of attraction (b) finite for all orbitals
(c) Zero for all orbitals (d) Zero for some orbitals and finite for others
3) When Zn metal is kept in CuSO4solution, copper is precipitated and ZnSO4is formed because:
(a) Atomic number of Zinc is smaller than copper
(b) Atomic number of Zinc is larger than copper
(c) Standard reduction potential of Zinc is more than that of copper
(d) Standard reduction potential of Zinc is less than that of copper
4) Electrolytes when dissolved in water, dissociate into their constituent ions, the degree of
dissociation of an electrolyte increases with the:
(a) Presence of a substance yielding common ion
(b) Decreasing temperature
(c) Decreasing concentration of electrolyte
(d) Increasing concentration of electrolyte
5) There is a large positive entropy change for an exothermic reaction. It means that the reaction
(a) possible at high temperatures only (b) impossible at all temperatures
(c) possible at low temperatures only (d) possible at all temperatures
6) Which of the following statement is false?
(a) the temperature of the system will fall if an exothermic reaction is isolated from its
(b) Energy is absorbed when one compound is converted into another with higher heat content
(c) the temperature of the system is likely to fall if heat is absorbed during the course of a
reaction(d) None of these
7) pH + pOH of a solution is:
(a) 7 (b) Zero (c) 14 (d) -14
8) The compound that is not Lewis acid:
(a) BF3 (b) BaCl2 (c) SnCl4 (d) AlCl3
9) Ore of Aluminium:
(a) Calamine (b) Dolomite (c) Bauxite (d) Limestone
10) Oxidation number of S in sulphuric acid:
(a) Four (b) Six (c) Two (d) Eight
11) d-block elements form coordination compounds because of:
(a) Small Cationic size (b) Large ionic Charge
(c) Unfilled d-orbitals (d) Filled d-orbitals
12) Brass is an alloy of:
(a) Cu and Zn (b) Cu, Ni, Zn (c) Cu and Ni (d) Cu, Al, Zn
13) Urea is a high quality nitrogenous fertilizer with:
(a) 76% nitrogen (b) 46% nitrogen (c) 66% nitrogen (d) 26% nitrogen
14) Diamond is:
(a) Good conductor of electricity (b) Bad conductor of electricity
(c) Bad conductor on heating (d) Good conductor on heating
15) Carbon monoxide is poisonous gas because it:
(a) replaces oxygen from lungs (b) forms carboxy haemoglobin
(c) Forms carbon dioxide with oxygen (d) has a sweet smell
16. Rust is:
(a) FeO + Fe(OH)2 (b) Fe2O3 + Fe(OH)2 (c) Fe2O3 (d) Fe2O3 + Fe(OH)3
17) Calcium Carbide reacts with water to give:
(a) Methane (b) Ethylene (c) Acetylene (d) Ethane
18. Which of the following substituent deactivates benzene ring and is o, p-directing?
(a) __ NH2 (b) __ Cl (c) __ OCH3 (d) __ OH
19) Which of the following is most readily nitrated?
(a) Toluene (b) Benzaldehyde (c) Nitrobenzene (d) Benzoic Acid
20) Ketones can be prepared by reaction of Grignard reagent with:
(a) Acid Amides (b) Acid Chloride (c ) Carboxylic Acid (d) Epoxides
21) Which of the following statements about the order of reaction is true?
(a) The order of a reaction can only be determined by experiment.
(b) A second order reaction is also bimolecular
(c) The order of reaction must be a positive integer
(d) The order of reaction increases with increasing temperature.
22 Polysaccharides yield many monosaccharides on:
(a) Hydration (b) Oxidation (c) Reduction (d) Hydrolysis
23) Which of the following is not aromatic?
(a) Benzene (b) cyclooctatetraene (c) Pyridine (d) Phenol
24) Which of the following is most basic?
(a) H2O (b) NH3 (c) CH3NH2 (d) CH3OH
25) Which of the following has lowest pH?
(a) CH3COOH (b) CF3COOH (c) ClCH2COOH (d) Cl3C COOH
26) The equilibrium of two readily interconvertible isomers is called:
(a) Stereoisomerism (b) Metamerism (c) Tautomerism (d) Polymorphism
27) Which of the following compounds exhibit geometrical isomerism?
(a) 1-Pentene (b) 2-Pentene (c) 2-methyl –2-Pentene (d) 2-methyl –2-Butene
28) Which of the following gives a tertiary alcohol when treated with Grignard reagent:
(a) HCHO (b) CH3CHO (c) C3H5CHO (d) CH3COCH3
29) Which of the following tests is not used to identify aldehydes?
(a) Tollen’s test (b) Benedict solution test (c) Fehling solution test (d) Ammonia test
30) Which is incorrect about alkaloids?
(a) Naturally Occuring (b) Possess a hetrocyclic ring
(c) Exhibit biological action (d) acidic in nature
31) Which of the followings will not give iodoform test:
(a) Acetone (b) Ethylacohol (c) Benzaldehyde (d) Acetaldehyde
32) The reaction of aniline with bromine water gives:
(a) o-bromoaniline (b) p-bromoaniline (c) 2,4-dibromoaniline (d) 2,4,6-tribromoaniline
33) The reaction of tripalmitin, with sodium hydroxide is called:
(a) Hydrolysis (b) Saponification (c) Esterification (d) Combustion
34) Which one is not Petrochemical?
(a) Napthalene (b) Mineral Oil (c) Wax (d) Table Salt
35) Chemical adsorption:
(a) is exothermic (b) is irreversible (c) takes place at high temp. (d) All of these
36) The most commonly used absorbent for chromatographic separation of organic compound is:
(a) Activated charcoal (b) Fuller’s Earth (c) Alumina (d) Silica gel
37) Grignard reagent is:
(a) Organo Zinc halide (b) Organo cadmium bromide
(c) n-Butyl Lithium (d) Organo Magnesium halide
38) Which one of the following is not a petrochemical.
(a) Cumene (b) Paraffin (c) Aluminum Chloride (d) Epoxy resin
39) The term syndiotactic is related to which one of the following?
(a) Synthetic detergents (b) Table Salt (c) Paraffin (d) Polyprophylene
40 Which one of the following is used as an Antibiotic?
(a) Patulin (b) Insulin (c) Soserine (d) Trypsin
41) Heroin is diacetate of:
(a) Papaverine (b) Morphine(c) Codeine (d) Thebaine
42) A reaction that practically is given by all organic compounds.
(a) Elimination (b) Friedel-Craft ecylation (c) Combustion (d) Rearrangement
43) Which functional group is present in polyester shirt?
(a) Lactam (b) Acid Chloride (c) Ether (d) Ester
(xviii) Which statement is true for Halogen (Halo-group)?
(a) Activating and O, p–directing (b) Activating and m–directing
(c) Deactivating and O, p–directing (d) None of these.
(44) Which one of the following can be synthesized from Aryl Diazonium Salt?
(a) Furfural (b) Carbylamine (c) Biphenyl (d) THF
(45 The Methyl group in Methyl Magnesium Iodide can act as:
(a) CH3Radical (b) CH3Carbonium ion (c) CH3Carbanion (d) Can react with a base
46) Nylon is a copolymer of:
(a) Urea and Formaldehyde (b) Phenol and Formaldehyde
(c) Hexamethylenediamine and adipic acid (d) Vinyl Chloride and Vinylalcohol
(47) Which of the following would react with one mole of Grignard’sreagent to yield a ketone?
(a) R R RCON ′ ′ ′ (b) R RCONH ′(c) RCONH2(d) RCOOH
48) Glyceraldehyde has one ofthe following properties:
(a) One asymmetric carbon atom(b) Two asymmetric carbon atoms
(c) A meso compound (d) Four asymmetric carbon atoms
49 The ant
ifreeze compound ethylene glycol has the formula:
(a) C2H5OH (b) CH3OH (c) C2H4(OH)2(d) C3H5(OH)3
50 Distillation is the best method for separating the two substances in which of the following:
(a) Water and salt dissolved
(b) water and a substance which does not dissolve in it
(c) Two liquids that have different boiling points
(d) Two solids that have different melting points.