Monday, December 17, 2007

Past JEE Questions Ch.5 Bonding and Molecular Structure

The linear structure is not assumed by
a) SnCl2
b) CS2
c) NO2+
d) HCN

Answer a

The molecule that will have no dipole meet is:
a) 2,2-dimethyl propene
b) Trans 2-pentene
c) cis-3-hexane

ans: d


Which of the following has zero dipole moment?
a) CLF
b) PCl3
c) SiF4
d) CFCl3

ans: c


Which is most ionic?
a) P2O5
b) MnO
c) CrO3
d) Mn2O7


The number and type of bonds between two carbon atoms in calcium carbide are

a) one σ , one π
b) one σ, two π
c) two σ , one π
d) one σ, 1½ π

Ans: b

Which one of the following compounds has sp2 hybridization
a) CO2
b) SO2
c) N2O
d) CO

ans: b

The geometry and type of hybrid orbital present about the central atom in BF3 is

a) linear, sp
b) trigonal planar, sp^2
c) tetrahedral, sp^3
d) pyramidal, sp^3

ans: b

The geometry of H2S and its dipole moment are:
a) angular and non-zero
b) angular and zero
c) linear and non-zero
d) linear and zero

2000 screening
Molecular shapes of SF4, CF4, and XeF4 are
a) the same with 2,0,1 lone pairs of electrons respectively
b) the same with 1,1,1,lone pairs of electrons respectively
c) different with 0,1,and 2 lone pairs of electrons respectively
d) different with 1,0, and 2 lone pairs of electrons respectively

ans: d

2001 screening
The correct order of bybridization of the central atom in the following species: NH3, [PtCl4]2-, PCl5 and BCl3 is

a) dsp^2, dsp^3, sp^2, and sp^3
b) sp^3, dsp^2,dsp^3,sp^2
c) dsp^3,sp^2,sp^3,dsp^3
d) dsp^2,sp^3,sp^2,dsp^3

ans: b

Among the following, the molecule with the highest dipole moment is:

(A) CH-3Cl (B) CH-2Cl-2
(C) CHCl-3 (D) CCl-4

answer A

JEE Question 2007 paper I

The percentage of p-character in the orbitals forming P–P bonds in 4 P is
(A) 25
(B) 33
(C) 50
(D) 75
Solution: (D)

Phosphorous will show sp^3 hybridisation having 75% p-character.
JEE Question 2007 paper I

Statement - 1

Boron always forms covalent bond


Statement - 2

The small size of B3^+ favours formation of covalent bond.

(A) Statement – 1 is True, Statement – 2 is True; Statement – 2 is a correct explanation for statement – 1
(B) Statement – 1 is True, Statement – 2 is True; Statement – 2 is Not a correct explanation for Statement – 1.
(C) Statement – 1 is True, Statement – 2 is False
(D) Statement – 1 is False, Statement – 2 is True

Answer: A


JEE Question paper II 2007

Among the following metal carbonyls, the C — O bond order is lowest in
(A) [Mn(CO)-6]^+

(B) [Fe(CO)-5]
(C) [Cr(CO)-6]
(D) [V(CO)-6]^-

answer: B

JEE 2006

If the bond length of CO bond in carbon monoxide is 1.128 A,
then what is the value of CO bond length in Fe(CO)-5?
(A) 1.15 A
(B) 1.128 A
(C) 1.72 A
(D) 1.118 A

Answer: (A)

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