Sigma Bond and Pi Bond

Q.

Assertion (A): All the carbon atoms in $H_{2}C=C=C{H}_2$ are $s{p}^2$ hybridised.

Reason (R): In this molecule all the carbon atoms are attached to each other by double bonds.

1. A is not correct but R is correct.

2. Both A and R are correct but R is not the correct explanation of A

3. Both A and R are correct and R is the correct explanation of A.

4. Both A and R are not correct.

Q. Why is $L{i}_{2}C{O}_3$ decomposed at a lower temperature whereas $N{a}_{2}C{O}_3$ at higher temperature?

Q.

How Antibonding Orbital is Formed?

Q. NaOH + PbO = x + H2O NaOH + SnO2 = y + H2O NaOH + H2O + Al = z + H2 Sum of number of atom present in one molecule each of x, y, z is a) 5 b) 10 c) 11 d) 15

Q.

Which single bond is strongest?

Q. The strength of sigma bonds formed by the axial overlap of $s$ - or $p$ - orbitals of $2^{nd}$ shell of the participating atoms decreases as:

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

Q. Which of the following cannot be explained by VBT?

1. Overlapping of orbitals
2. Bond formation
3. Paramagnetic nature of $O_2$
4. None of these

Q. $C_3^{4-}$ has

1. Two $\sigma$ and two $\pi$ bonds
2. Three $\sigma$ and one $\pi$ bonds
3. Two $\sigma$ and one $\pi$ bonds
4. Two $\sigma$ and three $\pi$ bonds

Q. Ionization enthalpy of gaseous Na atom is 495.5 kJ/mol. The lowest possible frequency of light that ionizes a sodium atom is (1) 1.24 x 10^15 s-1 (2) 3.15 x 10^15 s-1 (3) 4.76 x 10^15 s-1 (4) 7.50 x 10^15 s-1

Q. 36.Calculate the ratio of frequency of electron in an orbit for 2nd shell of Li+2 to 3rd shell of He+ ion?

Q. Identify a molecule which does not exist.
(NEET 2020)

Q.

Difference between homogeneous and heterogeneous mixture.

Q.

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

(a) C₂H₂ (b) C₂H₄

Q. Which of the following orbital overlaps are not allowed?

1. 
   
2. 
   
3. 
   
4. 
   
   

Q. The failure of VBT to explain the tetrahedral geometry 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. $C{H}_4$ is ionic
3. It contains coordinate covalent bond
4. All of the above

Q.

What is a triple bond?

Q.

Describe the hybridisation in case of PCl₅. Why are the axial bonds longer as compared to equatorial bonds?

Q. Choose the correct statement according to the valence bond theory:

1. A $\sigma$-bond is stronger than a $\pi$-bond
2. $s$-orbitals never form $\pi$-bonds
3. There can be only one sigma bond between two atoms
4. All of the above.

Q. How many degrees of freedom does a triatomic molecule like CO2 has ?

Q. Assertion :$N{H}_3$ gas is more easily liquefiable than $C{O}_2$ gas. Reason: $N{H}_3$ gas has higher critical temperature than that of $C{O}_2$ gas.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. The number of $\sigma$ and $\pi$ bonds in a molecule of benzene is

1. $6\sigma$ and $9\pi$
2. $9\sigma$ and $3\pi$
3. $12\sigma$ and $3\pi$
4. $6\sigma$ and $6\pi$

Q. 39. In which case extent of overlap is max? 1 S-S 2 S-P 3 P-P 4 same in every case

Q. 14. Show all resonance structures in the tertiary allylic

Q. How many sigma and pi- bonds are there in the molecule of dicyanoethene?

1. 3 sigma and 3 pi bonds
2. 5 sigma and 2 pi bonds
3. 2 sigma and 3 pi bonds
4. 7 sigma and 5 pi bonds

Q. The percentage of tetrahedral void occupied by dimond

Q. What is the number of $\sigma$ & $\pi$ bond in propene?

Q.

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

(a) C₂H₂ (b) C₂H₄

Q. resonance structure of C6H5BH2 ?? is there no resonance between the benzene ring and the BH2 group? why?

Q. In the given reaction 3I_2 +OH^-→ IO_3^- 5I^- 2 moles of iodine are taken then the ratio of iodate and iodide ions formed in the alkaline medium i

Q. What is the hybridization of phosphine?

1. $sp$ hybridized
2. $s{p}^2$ hybridized
3. $s{p}^3$ hybridized
4. No hybridization