Chemical Bonding · JEE Main previous year questions

2012 7 questions

1. Q652012 · 26 May 2012 · Shift 1

   Dipole moment is shown by

   1. A.1,2-dichlorobenzene
   2. B.trans-2,3-dichloro-2-butene
   3. C.1,4-dichlorobenzene
   4. D.trans-1,2-dinitroethene
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   Answer: A

2. Q652012 · 12 May 2012 · Shift 1

   The formation of molecular complex $\mathrm{B}{\mathrm{F}}_3-\mathrm{N}{\mathrm{H}}_3$ results in a change in hybridization of boron

   1. A.from $s{p}^2$ to $ds{p}^2$
   2. B.from $s{p}^2$ to $s{p}^3$
   3. C.from $s{p}^3$ to $s{p}^2$
   4. D.from $s{p}^3$ to $s{p}^{3}d$
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   Answer: B

3. Q662012 · 12 May 2012 · Shift 1

   Although $\mathrm{C}{\mathrm{N}}^{-}$ ion and ${\mathrm{N}}_2$ molecule are isoelectronic, yet ${\mathrm{N}}_2$ molecule is chemically inert because of

   1. A.presence of more number of electrons in bonding orbitals
   2. B.low bond energy
   3. C.absence of bond polarity
   4. D.uneven electron distribution.
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   Answer: C

4. Q672012 · 12 May 2012 · Shift 1
   
   1. A.
   2. B.
   3. C.
   4. D.
   Show answer

   Answer: B

5. Q682012 · 7 May 2012 · Shift 1

   Which of the following cannot be represented by resonance structures?

   1. A.Dimethyl ether
   2. B.Nitrate anion
   3. C.Carboxylate anion
   4. D.Toluene
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   Answer: A

6. Q752012 · 7 May 2012 · Shift 1

   The $d$-electron configurations of $\mathrm{C}{\mathrm{r}}^{2+}$, $\mathrm{M}{\mathrm{n}}^{2+}$, $\mathrm{F}{\mathrm{e}}^{2+}$ and $\mathrm{C}{\mathrm{o}}^{2+}$ are $d^4$, $d^5$, $d^6$ and $d^7$ respectively. Which one of the following will exhibit the lowest paramagnetic behaviour? (Atomic no. $\mathrm{Cr}=24$, $\mathrm{Mn}=25$, $\mathrm{Fe}=26$, $\mathrm{Co}=27$).

   1. A.$[\mathrm{Co}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$
   2. B.$[\mathrm{Cr}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$
   3. C.$[\mathrm{Mn}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$
   4. D.$[\mathrm{Fe}({\mathrm{H}}_2\mathrm{O}{)}_6{]}^{2+}$
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   Answer: A

7. Q822012 · 7 May 2012 · Shift 1

   Based on lattice energy and other considerations, which one of the following alkali metal chloride is expected to have the highest melting point?

   1. A.$\mathrm{NaCl}$
   2. B.$\mathrm{KCl}$
   3. C.$\mathrm{LiCl}$
   4. D.$\mathrm{RbCl}$
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   Answer: A