IIT JEE Important Questions
1. Among the following ions, the pπ and dπ overlap will be present in
A) SO3 B) SO42- C) CO32- D) NO3 –
2. Which of the following molecules have unequal bond length?
A) NF3 B) SF4 C) SF6 D) PF5
3. The sizes of the following hydrated ions are in the order
A) Li+ < Na+ < K+ B) K+ < Li+ < Na+
C) K+ < Na+ < Li+ D) Ca2+ > Sr2+> Ba2+
4. Which of the oxides reacts with both, an acid and alkali, is
A) ZnO B) SnO2 C) Al2O3 D) NO
5. Which of the following species are isoelectronic isoelectronic
with NH4+
A) N3– B) O2– C) S2– D) Al3+
6. Which of the following hydrides are ionic?
A) CaH2 B) BaH2 C) SrH2 D) BeH2
7. Which of the following hydroxide is soluble in water?
A) Be(OH)2 B) Mg(OH)2 C) Ca(OH)2 D) Ba(OH)2
8. Which of the following are correct?
A) Magnesium with dil. HNO3 produces hydrogen
B) H2O2 bleaches by oxidation
C) H2O2 reduces KMnO4 only in alkaline medium
D) The position of hydrogen is not fixed in periodic table
9. 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
10. The pairs with identical values of magnetic moments
A) Zn2+, Cu+ B) Co2+, Ni2+ C) Mn4+, Co2+ D) Mg2+, Sc+
11. In the following reactions, hybridization of the underlined atom is affected
A) PCl 5 (solid) dissociates into PCl 4 + and PCl 6-
B) LiH reacts with AlH3 forming LiAlH4
C) NH3 is protonated
D) H3PO2 is heated forming PH3 and H3PO3
12. Relationship λ = h/p is true for
A) photons B) protons C) electrons D) positrons
13. Which of the following are postulates of kinetic theory of gases?
A) Gases consist of discrete molecules
B) Actual volume occupied by gas molecules (M/NA) times the volume of the container where M and NA represent molecular weight of gas and Avagadro’s number respectively
C) Molecules are in constant randomn motion and have constant kinetic energy at all temperature
D) No force of attraction or repulsion exists between gas molecules
14. 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.
15. Li does not resemble other alkali metals in the following properties
A) Li2CO3 decomposes into oxides
B) LiCl is predominantly covalent
C) Li3N is stable
D) LiF is insoluble in water
16. Mn+ + NaOH →coloured ppt. The coloured ppt is insoluble in excess of alkali. The metal ion may be
A) Fe2+ B) Fe3+ C) Cu2+ D) Zn2+
17. PbCl4 exists but PbBr4 and PbI4 do not because of
A) Br– and I– are large size ions
B) Br2 and I2 are electro negative
C) Chlorine is a gas
D) Br– and I– are reducing agents
18. 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.
19. 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
20. 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
21. 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
22. 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
23. C4H10O formula will show
A) matamerism
B) functional isomerism
C) position isomerism
D) chain isomerism
24. 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
25. 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
26. Which of the following shows tautomerism?
A) C6H5OH
B) CH3NO2
C) C6H5CH2NO2
D) (CH3)3CNO2
27. 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.
28. Pick up the correct statement
A) II is more soluble than I in H2O
B) II is more soluble than III in H2O
C) II is less soluble than III in H2O
D) III is more soluble than I in H2O
29. Which are the species in which sulphur undergoes sp3 hybridisation?
A) SF4 B) SCl 2 C) SO42- D) H2S
KEY
1)AB 2)BD 3)CD 4)ABC 5) ABC 6)ABC 7) BCD 8) ABD 9) BCD 10)AD 11)AB 12)BC 13)AD 14) AC 15) ABC 16) ABC 17) AD 18) ABD 19)BD 20)AB 21)ABC 22) ABD 23) ABCD 24) ACD 25) ABCD 26) ABC 27) BD 28) ACD 29) BCD