Following are model questions for JEE Main Chemistry examination. These are called as ‘More than one correct answer questions’. You can practice these questions to secure good marks in the IIT JEE Main exam (New Pattern) to be conducted by Joint Admission Board of IITs. Answers are available at the end of the questions.
1. If temperature of a gas is raised, which of the following would be true?
A) Fraction of the molecules possessing most probable velocity will increase
B) Fraction of the molecules possessing most probable velocity will decrease
C) Fraction possessing very low velocity will decrease
D) Fraction possessing very high velocity will increase
2. Correct statements are
A) molar volume of every gas at STP is 22.4L
B) Under critical states compressibility factor is 1
C) All gases will have equal value of average KE at a given temperature.
D) at absolute zero, KE = 3/2 R.
3. From Maxwell Boltzmann distribution curve, the conclusions are
A) there is only a small number of molecules with very low velocities or very high velocities
B) largest number of molecules have a velocity corresponding to the maximum of the curve, which is most probable velocity
C) most probable velocity decreases on increasing temperature
D) distribution of the molecules in the given velocity range decreases on increasing temperature.
4. The molecules that will have dipole moment are
A) 2, 2-dimeethylpropane B) cis-3-hexene
C) 2, 2, 3, 3-tetramethylbutane D) trans-2-pentene
5. Which of the following statements is/ are incorrect regarding two organic compounds A and B which are stereoisomers?
A) They must be enantiomers B) They must be geometrical isomers
C) They can be diastereomers D) They can be meso compounds
6. Which are not isomers?
A) Methanol and methoxy methane
B) Ethyl alcohol and diethyl either
C) Acetone and acetaldehyde
D) Propionic acid and methyl acetate
7. About mesotartaric acid which of the following statements is/ are not correct?
A) It is optically inactive because it contains 2 asymmetric C atoms in its molecule
B) It can be separated into two optically active isomers
C) It cannot be separated into two optically active isomers
D) It is optically inactive due to external compensation
8. Which of the following statements is/ are true about the quantum numbers n, l , m and s?
A) l gives an idea of the shape of the orbital
B) m gives the information of the energy of electron in a given orbital
C) n gives the idea of the size of the orbital
D) s gives the direction of spin of electron in an orbital
9. Which of the following is correct under the same conditions of pressure and temperature?
A) Hydrogen diffuses 4 times faster than oxygen
B) Hydrogen diffuses 2.83 times faster than methane
C) Helium escapes at a rate 2 times as fast as methane does
D) Helium escapes at a rate 4 times as much as sluphur dioxide
10. Select incorrect statements
A) Molar volume of every gas at STP is 22.4L
B) Under critical states compressibility factor is 1
C) All gases will have equal value of average KE at given temperature.
D) At absolute zero, KE is 3/2 R.
KEY: 1) BCD 2) AC 3) ABD 4)BD 5)AB 6)ABC 7) ABD 8) ACD 9) ABCD 10) BD.