Education. Crypto. Finance. Health. Travel. Culture. Celebrities. The helpnow pk Local covers news, health Issues, Education, culture, technology, and much more via its articles, podcasts, videos, and flagship magazine.
Table of Contents
PPSC Lecturer of Chemistry Past Paper pdf
PPSC Lecturer of Chemistry and S S Past Paper pdf
When an electron is brought from infinite distance close to the nucleus of the atom, the energy of Electron-nucleus system?
(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
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
When Zn metal is kept in CuSO4 solution, copper is precipitated and ZnSO4 is 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
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
There is a large positive entropy change for an exothermic reaction. It means that the reaction will be:
(a) possible at high temperatures only
(b) impossible at all temperatures
(c) possible at low temperatures only
(d) possible at all temperatures
Which of the following statement is false?
(a) the temperature of the system will fall if an exothermic reaction is isolated from its surroundings
(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
The H_____ bond is strongest in:
(a) S__H ……O
(b) O_H …….S
(c) F_H ……..O
(d) F_H ……..S
Heavy water contains:
(a) Large amount of salts
(b) Deuterium
(c) O18
(d) O16
pH + pOH of a solution is:
(a) 7
(b) Zero
(c) 14
(d) -14
The compound that is not Lewis acid:
(a) BF3
(b) BaCl2
(c) SnCl4
(d) AlCl3
Strongest acid having Ka:
(a) 104
(b) 10-4
(c) 1
(d) 10-2
Ore of Aluminium:
(a) Calamine
(b) Dolomite
(c) Bauxite
(d) Limestone
Oxidation number of S in sulphuric acid:
(a) Four
(b) Six
(c) Two
(d) Eight
d-block elements form coordination compounds because of:
(a) Small Cationic size
(b) Large ionic Charge
(c) Unfilled d-orbitals
(d) Filled d-orbitals
Brass is an alloy of:
(a) Cu and Zn
(b) Cu, Ni, Zn
(c) Cu and Ni
(d) Cu, Al, Zn
Urea is a high quality nitrogenous fertilizer with:
(a) 76% nitrogen
(b) 46% nitrogen
(c) 66% nitrogen
(d) 26% nitrogen
Diamond is:
(a) Good conductor of electricity
(b) Bad conductor of electricity
(c) Bad conductor on heating
(d) Good conductor on heating
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
Rust is:
(a) FeO + Fe(OH)2
(b) Fe2O3 + Fe(OH)2
(c) Fe2O3
(d) Fe2O3 + Fe(OH)3
Calcium Carbide reacts with water to give:
(a) Methane
(b) Ethylene
(c) Acetylene
(d) Ethane
Which of the following substituent deactivates benzene ring and is o, p-directing?
(a) __ NH2
(b) __ Cl
(c) __ OCH3
(d) __ OH
Which of the following is most readily nitrated?
(a) Toluene
(b) Benzaldehyde
(c) Nitrobenzene
(d) Benzoic Acid
Ketones can be prepared by reaction of Grignard reagent with:
(a) Acid Amides
(b) Acid Chloride
(c ) Carboxylic Acid
(d) Epoxides
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.
PPSC Lecturer of Chemistry Past Paper 2015
Polysaccharides yield many monosaccharides on:
(a) Hydration
(b) Oxidation
(c) Reduction
(d) Hydrolysis
Which of the following is not aromatic?
(a) Benzene
(b) cyclooctatetraene
(c) Pyridine
(d) Phenol
Which of the following is most basic?
(a) H2O
(b) NH3
(c) CH3 NH2
(d) CH3OH
Which of the following has lowest pH?
(a) CH3COOH
(b) CF3COOH
(c) ClCH2COOH
(d) Cl3C COOH
The equilibrium of two readily interconvertible isomers is called:
(a) Stereoisomerism
(b) Metamerism
(c) Tautomerism
(d) Polymorphism
Which of the following compounds exhibit geometrical isomerism?
(a) 1-Pentene
(b) 2-Pentene
(c) 2-methyl –2-Pentene
(d) 2-methyl –2-Butene
Which of the following gives a tertiary alcohol when treated with Grignard reagent:
(a) HCHO
(b) CH3CHO
(c) C3H5CHO
(d) CH3COCH3
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
Which is incorrect about alkaloids?
(a) Naturally Occuring
(b) Possess a hetrocyclic ring
(c) Exhibit biological action
(d) acidic in nature
Which of the followings will not give iodoform test?
(a) Acetone
(b) Ethylacohol
(c) Benzaldehyde
(d) Acetaldehyde
The reaction of aniline with bromine water gives:
(a) o-bromoaniline
(b) p-bromoaniline
(c) 2,4-dibromoaniline
(d) 2,4,6-tribromoaniline
The reaction of tripalmitin, with sodium hydroxide is called:
(a) Hydrolysis
(b) Saponification
(c) Esterification
(d) Combustion
Which one is not Petrochemical?
(a) Napthalene
(b) Mineral Oil
(c) Wax
(d) Table Salt
Chemical adsorption:
(a) is exothermic
(b) is irreversible
(c) takes place at high temp.
(d) All of these
The most commonly used absorbent for chromatographic separation of organic compound is:
(a) Activated charcoal
(b) Fuller’s Earth
(c) Alumina
(d) Silica gel
Grignard reagent is:
(a) Organo Zinc halide
(b) Organo cadmium bromide
(c) n-Butyl Lithium
(d) Organo Magnesium halide
Which of the following compounds exhibit geometrical isomerism?
(a) 1-Pentene
(b) 2-Pentene
(c) 2-methyl –2-Pentene
(d) 2-methyl –2-Butene
There is a large positive entropy change for an exothermic reaction. It means that the reaction will be:
(a) possible at high temperatures only
(b) impossible at all temperatures
(c) possible at low temperatures only
(d) possible at all temperatures
Which of the following statement is false?
(a) the temperature of the system will fall if an exothermic reaction is isolated from its surroundings
(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
Which one is not petrochemical?
(a) Napthalene
(b) Mineral Oil
(c) Wax
(d) Table Salt
If the rate of a reaction does not change with time then the reaction should be:
(a) moderately slow
(b) very fast
(c) catalyzed
(d) zeroth order
(e) None of these.
If a chemical reaction reaches equilibrium state:
(a) its forward and backward rates are equal
(b) its overall free energy change becomes zero
(c) its equilibrium constant is the ratio of the two rate constants
(d) all of these
(e) none of these
PCl5(g) ® PCl3(g) +Cl2(g). The units of equilibrium constant, Kc for the reaction is:
(a) L mol–1
(b) mol L –1
(c) mol –1 L –1
(d) mol –2 L–2
(e) None of these
Energy of a typical H – bond ranges between:
(a) 2 to 4 kJmol –1
(b) 5 to 10 kJmol –1
(c) 15 to 30 kJmol –1
(d) 40 to 80 kJmol –1
(e) None of these
Which of the pairs makes an “ideal mixture”?
(a) benzene-methanol
(b) benzene-toluene
(c) ethanol-methanol
(d) ethanol-water
(e) None of these
Which of the following concentration units depends on temperature?
(a) molarity
(b) molality
(c) mole fraction
(d) weight to weight (W/W) %
(e) None of these
A 0.4% (W/V) aqueous solution of NaOH is nearly:
(a) 1 M
(b) 0.5 M
(c) 0.1 M
(d) 0.01 M
(e) None of these
Which of the followings is correct for the ground state of O2 molecule?
(a) bond order two and no unpaired electron
(b) bond order two and one unpaired electron
(c) bond order two and two unpaired electron in the bonding orbital
(d) bond order two and two unpaired electrons in the anti-bonding orbital
(e) None of these
Which one should give the simplest proton NMR spectrum?
(a) CH3CH2OH
(b) CH3OH
(c) CH3OCH3
(d) CH3CHO
(e) all are equally complicated
PPSC Lecturer of Chemistry Past Paper 2016
Which group has the highest stretching frequency of IR-region in the gas phase?
(a) º C -H
(b) = C -H
(c) – O – H
(d) – N – H
(e) all are equal
Which of the following should not be formed according to the bonding theories?
(a) H +
2 (b) H –
2 (c) He 2
(d) He2
+ (e) None of these
There remains no liquid-vapour boundary at:
(a) boiling point
(b) critical temperature
(c) triple point
(d) azeotrope composition
(e) None of these
For a catalyzed reaction as compared to the unanalyzed one:
(a) heat of reaction is higher
(b) heat of reaction is lower
(c) heat of reaction is same
(d) activation energy is same
(e) All above are correct
When two ideal gases at the same temperature are mixed together:
(a) there is a negative heat of mixing
(b) there is a positive heat of mixing
(c) both heat and entropy of mixing are positive
(d) entropy of mixing alone is positive
(e) All above are correct
Which of the series is present in the ultraviolet region for the H – atom?
(a) Layman
(b) Balmer
(c) Paschen
(d) Pfund
(e) None of these
pH of 0.01 M HCl solution should be:
(a) 3
(b)2
(c)1.5
(d) 1
(e) None of these
Which of the ions should exhibit highest electrical mobility in aqueous solution?
(a) Na+
(b) I
(c) Cs+
(d) Cd++
(e) Li+
H2 + Br2 ® 2HBr is a very famous gas phase reaction. The overall order of this Reaction is:
(a) two
(b) one (c) half
(d) one half in the beginning
(e) All above are correct
Presence of a chiral center in molecules makes them:
(a) absorb uv–radiation
(b) absorb plane polarized light
(c) rotate plane polarized light
(d) emit IR–radiation
(e) None of these
When an electron is brought from infinite distance close to the nucleus of the atom, the energy of Electron-nucleus system?
(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
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
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
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
There is a large positive entropy change for an exothermic reaction. It means that the reaction will be:
(a) possible at high temperatures only
(b) impossible at all temperatures
(c) possible at low temperatures only
(d) possible at all temperatures
Which of the following statement is false?
(a) the temperature of the system will fall if an exothermic reaction is isolated from its
Surroundings
(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
pH + pOH of a solution is:
(a) 7
(b) Zero
(c) 14
(d) -14
The compound that is not Lewis acid:
(a) BF3
(b) BaCl2
(c) SnCl4
(d) AlCl3
Ore of Aluminium:
(a) Calamine
(b) Dolomite
(c) Bauxite
(d) Limestone
Oxidation number of S in sulphuric acid:
(a) Four
(b) Six
(c) Two
(d) Eight
Identify two words that sound alike but are spelled differently, which mean: a straight line connecting two points on a curve rope (Ans. chord, cord;)
PPSC Lecturer of Chemistry Past Paper 2017
