WBJEE Engineering & Medical Questions & Answers

I want to give entrance exam of West Bengal Joint Entrance Examination .Will you provide previous exam Questions & Answers of Chemistry for an idea?

[Kiran Chandar]

Below Questions & Answers of Chemistry subject of WBJEE (West Bengal Joint Entrance Examination) is given.

Which of the following sets of quantum numbers (n,l,ml,ms) correctly represents an electron in the 5f subshell?
A. 5, 3, 4, +½
B. 5, 2, 1, 0
C. 5, 3, −2, +½
D. 5, 5, 2, −½

(S)-(+)-lactic acid and (R)-(–)-lactic acid are nonsuperposable mirror images of each other. They are called
A. diastereomers
B. tautomers
C. enantiomers
D. structural isomers

A reducing agent
A. loses electrons and is reduced.
B. gains electrons and is reduced.
C. loses electrons and is oxidized.
D. gains electrons and is oxidized.

Which of the following species has the maximum number of unpaired d-electrons?
A. Zn
B. Fe2+
C. Ni2+
D. Cu+

Arrange the following in decreasing order of reactivity with HCN. HCHO, CH3CHO, CH3COCH3
A. HCHO > CH3CHO > CH3COCH3
B. CH3CHO > HCHO > CH3COCH3
C. CH3COCH3 > CH3CHO > HCHO
D. CH3CHO > CH3COCH3 > HCHO=


Cadmium rods are used for which purpose?
A Emit electrons
B Absorb neutrons
C Emit neutrons
D Absorb electrons
Question 2
Propionic acid and KOH reacts to produce which one of the following?
A Potassium propionare
B Propyl alcohol
C Propionaldehyde
D Does not react
Question 3
What is the effect of dilution on the equivalent conductance of Strong electrolyte?
A Decrease on dilution
B Remains unchanged
C Increase on dilution
D None of the above
Question 4
35.4 ml.. of HCI is required for the neutralization of a solution containing 0.275 g of sodium hydroxide. The normality of hydrochloric acid is?
A 0.97 N
B 0.142 N
C 0.194 N
D 0.244 N
Question 5
A liquid is in equilibrium with its vapour at its boiling point. On the average, the molecules in two phases have equal
A inter- molecular forces
B potential energy
C kinetic energy
D total energy
Question 6
Which one of the following pairs is obtained on heating ammonium dlchromate?
A N2 and H2O
B N and H20
C NO2 and H
D NO and NO2
Question 7
1 mole of photon, each of frequency 2500 s, would have approximately a total energy of
A l erg
B 1J
C 1 eV
D 1 MeV
Question 8
Which relatiou
A dG=Vdp-SdT
B dE=pdV+TdS
C dH=-Vdp+TdS
D dG=Vdp+SdT
Question 9
The ease of dehydrohalogenation of ailcyl halide with alcoholic KOH is
A 3°<2°<1°
B 3°>2°>1°
C 3°<2°>1°
D 3>2°<1°
Question 10
When H2S gas is passed in a metal sulphate solution in presence of NH4OH, a white precipitate is produced. The metal is identified as:
A Zn
B Fe
C Pb
D Hg
Question 11
The pair of compound which cannot exists together in solution is
A NaHCO3 and NaOH
B Na2CO3 and NHCO3
C Na2CO3 and NaOH
D NaHCO3 and NaCl
Question 12
Which one of the following processes is used for the manufacture of calcium?
A Reduction of CaO with carbon
B Reduction of CaO with hydrogen
C Electrolysis of a mixture ofanhydrousCaCl2 and KCI
D Electrolysis of molten Ca (0H2)
Question 13
The time taken for 10% completion of a first order reaction is 20 mm. Then, for 19% completion, the reaction will take
A 40min
B 6Omin
C 30 mm
D 50 mm
Question 14
Explain why aniline is not as basic as ammonia?
A 0.59 V
B 0.00 V
C — 0.59 V
D — 0.059
Question 15
The correct order of decreasing acidity of nitrophenols will be
A m -nitrophenol >p-nitrophenol> o-nitrophenol
B o-nitrophenol> m-nitrophenol> p-nitrophenol
C p-nitrophenol > m-nitrophenol> o.nitrophenoI
D p-nitxophenol > o-nitrpheno1> m-nitrophenol
Question 16
The molecule having largest dipole moment among the following is:
A CHI3
B CH4
C CHCI3
D CC14
Question 17
Which has maximum number of atoms?
A 24gofC
B 56gofFe
C 26gofAI
D 108gofAg
Question 18
Fe(OH)3 can be separated from AI(OH)3 by the addition of
A NaCI solution
B dil. HCl solution
C NaOH solution
D NH4Cl and NH0H
Question 19
Which of the following will decrease the pH of a 50 mL solution of 0.01 M HC1?
A Addition of 5 mL of 1 M HC1
B Addition of 50 mL of 0.01 M HCI
C Addition of 50 mL of 0.002 M HCI
D Addition of Mg
Question 20
For a reversible chemical reaction where the forward process is exothermic, which of the following statements is correct?
A The backward reaction has higher activation energy than the forward reaction
B The backward and the forward processes have the same activation energy
C The backward reaction has lower activation energy
D


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