Engineering Entrance Sample Papers

JEE Mains Chemistry Sample Paper This chemistry sample paper is based on JEE Mains (AIEEE) chemistry exam pattern, for complete details about JEE Exam follow the link: JEE Exam

Question: An atomic solid crystallizes in a body centre cubic lattice and the inner surface of the atoms at the adjacent corner are separated by 60.3 pm. If the atomic weight of A is 48, then density of the solid, is nearly
(a) 2.7 g/cc
(b) 5.07 g/cc
(c) 3.5 g/cc
(d) 1.75 g/cc
Ans: (d)

Question: An organic compound containing C, H and N gave following analysis : C = 40%, H = 13.33% and N = 46.67%. Its empirical formula would be
(a) C2H7N2
(b) CH5N
(c) CH4N
(d) C2H7N
Ans. (c)

Question: Acetylene and hydrogen fluoride react to give difluoroethane when one mole of C2H2 and 5 mole of HF are reacted in a 10 litre flask. What will be the pressure in the flask at 0°C, when the reaction is complete?
(a) 8.965 atm
(b) 9.865 atm
(c) 7.985 atm
(d) 8.265 atm
Ans: (a)

Question: A base, C17H21O4N is soluble in water to the extent of 1.7 g litre-1 and a saturated solution has a pH of 10.08. The value of ionization constant, Kb for this base is
(a) 5.6 x 10-6
(b) 1.2 x 10-6
(c) 2.62 x 10-6
(d) 9.04 x 10-6
Ans: (c)

Question: An unspecified quantity of an ideal gas has an initial pressure of 5 atm and temperature is 30oC. The gas is expanded at 30oC until the volume has increased by 60% of the initial value. Next, the quantity of the gas in the vessel is increased by 20% of the initial value while volume is maintained constant. Finally, the temperature is adjusted at constant volume until the gas pressure is again 5 atm, what is the final temperature?
(a) 400 K
(b) 404 K
(c) 100 K
(d) 50 K
Ans: (b)

Question: The solubility of C6H5NH3+Cl would be highest, among the following solvents in
(a) acidic buffer of pH = 3
(b) basic buffer of pH = 10
(c) neutral buffer of pH = 7
(d) pure water
Ans: (b)

Question: It is desired to prepare a phosphate buffer of pH = 7.60 by using conjugate base of the phosphoric acid as the acid and its conjugate base as the conjugate base. What must be the concentration of conjugate acid and conjugate base to produce this pH? Given pKa = 7.21
(a) 0.10 M and 0.245 M respectively
(b) 0.245 M and 0.10 M respectively
(c) 0.10 M and 0.345 M respectively
(d) 0.345 M and 0.10 M respectively
Ans: (a)

Question: Which of the following statements for crystals having Frenkel defect is not correct?
(a) Frenkel defects are observed where the difference in sizes of cations and anions is large
(b) The density of crystals having Frenkel defect is lesser than that of a pure perfect crystal
(c) In an ionic crystal having Frenkel defect may also contain Schottky defect
(d) Usually alkali halides do not have Frenkel defect
Ans: (b)

Question: An ideal solution was found to have a vapour pressure of 80 torr when the mole fraction of a non-volatile solute was 0.2. What would be the vapour pressure of the pure solvent at the same temperature?
(a) 64 torr
(b) 80 torr
(c) 100 torr
(d) 400 torr
Ans: (c)

Question: In carbonium ion the carbon bearing the positive charge in the
(a) sp2-hybridized state
(b) sp3d-hybridized state
(c) sp-hybridized state
(d) sp3-hybridized state
Ans. (a)

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Question: From separate solutions of four sodium salts NaW, NaX, NaY, NaZ had pH 7.0, 9.0, 10.0, 11.0 respectively. When each solution was 0.1 m, the strongest acid is
(a) HW
(b) HX
(c) HY
(d) HZ
Ans: (a)

Question: Among the halobenzenes, the one that undergoes electrophilic aromatic substitution most readily and the reason for its higher reactivity are:
(a) fluorobenzene; the benzenonium ion intermediate is stabilized by 2p(F), 2p(C) overlap which is most efficient
(b) chlorobenzene; very high electron affinity of chlorine considerably lowers the energy of activation of the reaction
(c) bromobenzene; high polarizing power of the halogen atom helps in effective stabilization of the benzenonium ion intermediate
(d) iodobenzene; iodine atom has the lowest electronegativity and hence electron density of the phenyl ring is least disturbed
Ans: (d)

Question: The O.P. of  equimolar solution of Urea, BaCl2 and AlCl3, will be in the order
(a) AlCl3 > BaCl2 > Urea
(b) BaCl2 > AlCl3 > Urea
(c) Urea > BaCl2 > AlCl3
(d) BaCl2 > Ureaa > AlCl3
Ans. (a)

Question: At a certain temperature, the first order rate constant k1 is found to be smaller than the second order rate constant k2. If the energy of activation (E1) of the first order reaction is greater than the energy of activation (E2) of the second order reaction, then as the temperature is raised
(a) k2 will increase faster than k1­.
(b) k1 will increase faster than k2 but will always remain less than k2.
(c) k1 will increase faster than k2 and become equal to k2.
(d) k1 will increase faster than k2 and become greater than k2.
Ans: (b)

Question: The property of hydrogen which distinguishes it from other alkali metals is
(a) its electropositive character
(b) its affinity for non metal
(c) its reducing character
(d) its non-metallic character
Ans: (d)

Question: Average atomic mass of magnesium is 24.31 a.m.u. A sample of magnesium is composed of 79 mole % of 24Mg and remaining 21 mole % of 25Mg and 26Mg. The number of moles
of 26Mg is
(a) 10
(b) 11
(c) 15
(d) 16
Ans: (a)

Question: In order to refine blister copper it is melted in a furnace and is stirred with green logs of wood. The purpose is
(a) to expel the dissolved gases in blister copper
(b) to bring the impurities to surface and oxidise them
(c) to increase carbon content of copper
(d) to reduce the metallic oxide impurities with hydrocarbon gases liberated from the wood
Ans: (d)

Question: Rearrange the following (I to IV) in the order of increasing masses
(I) 0.5 moles of O3
(II) 0.5 gm atom of oxygen
(III) 3.011 x 1023 molecules of O2
(IV) 5.6 litre of CO2 at STP
(a) II < IV < III < I
(b) II < I < IV < III
(c) IV < II < III < I
(d) I < II < III < IV
Ans: (a)

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Question: PbS can be separated from ZnS by electrostatic separation method. The property utilized in this method is
(a) PbS is a good conductor and ZnS is a bad conductor of electricity
(b) PbS is a bad conductor and ZnS is a good conductor of electricity.
(c) Both PbS and ZnS are good conductors.
(d) Both PbS and ZnS are bad conductors
Ans: (a)

Question: Consider the following statements regarding micelles
1. At critical micelle concentration, several properties of solution of surfactant such as molar conductivity, surface tension and osmotic pressure undergo a dramatic change.
2. Micelles from ionic surfactants can be formed only above a certain temperature called the Kraft temperature.
3. The enthalpy of micelle formation in aqueous systems in slightly negative.
Which of the above statement is/are correct?
(a) 1 alone
(b) 1 and 2
(c) 1, 2 and 3
(d) 1 and 3
Ans: (b)

Question: Which of the following metal sol cannot be prepared by Bredig’s arc method?
(a) K
(b) Cu
(c) Au
(d) Pt
Ans: (a)

Question: What is formed when calcium carbide react with heavy water
(a) C2D
(d) CD2
Ans. (a)

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Question: Sorption is the phenomenon
(b) reverse of absorption
(c) when adsorption and absorption takes place simultaneously
(d) none of these
Ans: (c)

Question: The prefixes syn and anti are used to denote
(a) conformational isomers
(b) geometrical isomers
(c) structural isomers
(d) optical isomers
Ans: (b)