Sigma Bond and Pi Bond

Q.

Which has the highest dipole moment and give the order ${\mathrm{CH}}_3\mathrm{Cl},{\mathrm{CH}}_2{\mathrm{Cl}}_2,{\mathrm{CHCl}}_3\mathrm{or}{\mathrm{CCl}}_4$

Q.

What is the total number of sigma and pi bonds in the following molecules?

(a) $C_2{H}_2$ (b) $C_2{H}_4$

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

1. One sigma, one pi
2. One sigma, two pi
3. Two sigma, one pi
4. Two sigma, two pi

Q.

What is the oxidation state of sulfur in ${\mathrm{SO}}_2$?

Q. How many sigma bonds are present in naphthalene?

1. 3
2. 19
3. 15
4. 20

Q. Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d⁵. The atomic number is .

1. 27
2. 26
3. 24
4. 25

Q. Which of the following is an electron deficient compound?

1. NaCI
2. $N{H}_3$
3. $BC{l}_3$
4. $PC{l}_3$

Q. The number of $s{p}^2-s{p}^2$ sigma bonds in the compound given below is:

1. 1
2. 3
3. 4
4. 5

Q. Alkenyne is the hydrocarbon which contains both double and triple bond in a single molecule. The third member of the family of alkenynes has the molecular formula:

1. $C_6{H}_6$
2. $C_5{H}_6$
3. $C_6{H}_8$
4. $C_4{H}_4$

Q.

Distinguish between a sigma and a pi bond.

Q.

The hybridization of atomic orbitals of nitrogen in ${\mathrm{NO}}_2^{+}$ , ${\mathrm{NO}}_3^{-}$and ${\mathrm{NH}}_4^{+}$are:

1. $\mathrm{sp},{\mathrm{sp}}^2\mathrm{and}{\mathrm{sp}}^3$ respectively

2. ${\mathrm{sp}}^2,{\mathrm{sp}}^3\mathrm{and}\mathrm{sp}$ respectively

3. ${\mathrm{sp}}^3,{\mathrm{sp}}^2\mathrm{and}\mathrm{sp}$ respectively

4. ${\mathrm{sp}}^3,\mathrm{sp}\mathrm{and}{\mathrm{sp}}^2$ respectively

Q. Assertion: Equal number of sigma and pi bonds are present in ethyne.
Reason: $\pi$-bond is stronger than sigma bond.

1. The assertion and the reason are true and the reason is the correct explanation of the assertion
2. The assertion and the reason are true but the reason is not the correct explanation of the assertion
3. The assertion is true but the reason is false
4. Both the assertion and the reason are false

Q. A $\pi$-bond is formed by the overlap of:

1. $s-s$ orbitals
2. $s-p$ orbitals
3. $p-p$ orbitals in end to end manner
4. $p-p$ orbitals in sideways manner

Q.

How does resonance affect stability?

Q. The strength of sigma bonds formed by the overlapping of atomic orbitals is in the order:

1. $s-s<s-p<p-p$
2. $s-s<p-p<s-p$
3. $s-p<s-s<p-p$
4. $p-p<s-s<s-p$

Q. Which type of overlapping results in the formation of a $\pi$ bond?

1. Axial overlapping of p-p orbitals
2. Axial overlapping of s-p orbitals
3. Axial overlapping of s-s orbitals
4. Lateral overlapping of p-p orbitals

Q. Which of the following statements are correct for the formation of a stable bond according to the valence bond theory?

1. The electrons should have opposite spins
2. The two atoms should be close to each other
3. Higher overlapping of the electron clouds
4. All are correct

Q.

What is a weak bond called?

Q.

3. Draw the structural formula of ethyne.

Q. The d-electron configuration of $C{r}^{2+},M{n}^{2+},F{e}^{2+}\text{and}C{o}^{2+}\text{are}{d}^4,d^5,d^6\text{and}{d}^7$ respectively. Which one of the following will exhibit minimum paramagnetic behaviour ?

(At, nos. $Cr=24,Mn=25,Fe=26,Co-27$)

1. $\left[Co\right(H_{2}O{)}_6{]}^{2+}$
2. $\left[Mn\right(H_{2}O{)}_6{]}^{2+}$
3. $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$
4. $\left[Cr\right(H_{2}O{)}_6{]}^{2+}$

Q.

Is a covalent bond stronger than a metallic?

Q. Which one of the following molecules is formed by $p-p$ overlapping?

1. $B{r}_2$
2. $HBr$
3. $H_{2}O$
4. $P{H}_3$

Q.

Oxidation number of sulphur in S₈, S₂F₂ and H₂S are:

1. +2, 0, +2

2. -2, 0, +2

3. 0, +1, -2

4. 0, +1, +2

Q. Given below are two statements: One is labelled as
Assertion A and the other is labelled as Reason R

Assertion A: Zero orbital overlap is an out of phase overlap.

Reason R: It results due to different orientation/direction of approach of orbitals.

In the light of the above statements, choose the correct answer from the options given below

1. A is false but R is true
2. Both A and R are true and R is the correct explanation of A
3. Both A and R are true but R is NOT the correct explanation of A
4. A is true but R is false

Q.

Do double bonds increase acidity?

Q.

The types of hybrid orbitals of nitrogen in $N{O}_2^{+},N{O}_3^{-}$ and $N{H}_4^{+}$ respectively are expected to be

1. $s{p}^2,sp\text{and}s{p}^3$
2. $s{p}^2,s{p}^3\text{and}sp$
3. $sp,s{p}^2\text{and}s{p}^3$
4. $sp,s{p}^3\text{and}s{p}^2$

Q. The failure of VBT to explain the tetrahedral geomerty of $C{H}_4$ is because:

1. All the $C-H$ bond distance and $H-C-H$ bond angles are equal in $C{H}_4$
2. It contains coordinate covalent bond
3. All of the above
4. $C{H}_4$ is ionic

Q. Which one of the following statements is not correct for sigma- and pi-bonds formed between two carbon atoms?

1. Sigma bond is stronger than a pi bond
2. Bond energies of sigma- and pi-bonds are of the order of $265\text{kJ/mol}$ and $346\text{kJ/mol}$, respectively
3. Free rotation of atoms about a sigma-bond is allowed but not in case of a pi-bond
4. Sigma-bond determines the direction between carbon atoms but a pi-bond has no effect in this regard

Q. Which of the following statements is not correct for sigma and pi bond formed between two carbon atoms?

1. Sigma bond determines the direction between carbon atoms but a pi bond has no primary effect in this regard
2. Sigma bond is stronger than a pi bond
3. Free rotation of atoms about a sigma bond is allowed but not in the case of pi - bond
4. Bond energies of sigma and pi bonds are of the order of 264 kJ/mol and 347 kJ/mol respectively

Q. Diamagnetic species are those which contain no unpaired electrons. Which among the following are diamagnetic?

1. $N_2^{2-}$
2. $O_2$
3. $N_2$
4. $O_2^{2-}$