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What is the total number of sigma and pi bonds in the following molecu...

What is the total number of sigma and pi | Class 11 Chemistry Chapter Chemical Bonding and Molecular Structure, Chemical Bonding and Molecular Structure NCERT Solutions

Welcome to the NCERT Solutions for Class 11 Chemistry - Chapter Chemical Bonding and Molecular Structure. This page offers a step-by-step solution to the specific question from Exercise 1, Question 28: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 28:

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

(a) C₂H₂ (b) C₂H₄

Answer:

Sigma (σ) bond is the bond formed when the two half -filled atomic orbitals overlap along their inter-nuclear axes. Sigma bond will always represent a single bond.

Pie (π) bond is formed when the two half- filled atomic orbitals belonging to the bonding atoms overlap along sides (sidewise or lateral overlap).

A double bond will always have one sigma bond and one pie bond.

A triple bond will always have one sigma bond and two pie bond. So from the structure of C₂H₂, it is clear that it has three sigma bonds and two pie bonds.

From the structure of C₂H₄,it is clear that it has five sigma bonds & one pie bond.

Other Questions of Chapter Chemical Bonding and Molecular Structure

Describe the change in hybridisation (if any) of the Al atom in the following reaction.

Write Lewis symbols for the following atoms and ions:

S and S2–; Al and Al3+; H and H–

What is meant by the term bond order? Calculate the bond order of: N₂, O₂,O₂⁺,and O₂^-.

Define hydrogen bond. Is it weaker or stronger than the van der Waals forces?

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

Write the significance of a plus and a minus sign shown in representing the orbitals.

Which hybrid orbitals are used by carbon atoms in the following molecules?

(a)CH₃–CH₃;

(b) CH₃–CH=CH₂;

(d) CH₃-CHO

(e) CH₃COOH

Considering x-axis as the internuclear axis which out of the following will not form a sigma bond and why?

(a) 1s and 1s

(b) 1s and 2p_x

(d) 1s and 2s.

Is there any change in the hybridisation of B and N atoms as a result of the following reaction?

BF₃ + NH₃ → F₃B.NH₃

What is meant by hybridisation of atomic orbitals? Describe the shapes of sp, sp^₂, sp³hybrid orbitals.

Popular questions of class 11 Chemistry

Calculate the amount of carbon dioxide that could be produced when

(i) 1 mole of carbon is burnt in air.

(ii) 1 mole of carbon is burnt in 16 g of dioxygen.

(iii) 2 moles of carbon are burnt in 16 g of dioxygen.

The mass of an electron is 9.1 × 10^–31 kg. If its K.E. is 3.0 × 10^–25 J, calculate its wavelength.

Calculate the wavelength of an electron moving with a velocity of 2.05 × 10⁷ ms^–1.

Balance the following redox reactions by ion – electron method :

(a) MnO₄^–(aq) + I^–(aq) → MnO_{2 (s)} + I_2(s) (in basic medium)

(b) MnO₄ ^– (aq) + SO_{2 (g)}→ Mn²⁺ (aq) + HSO₄^– (aq) (in acidic solution)

(d) Cr₂O₇ ^2– + SO_2(g) → Cr³⁺ _(aq) + SO₄^2–(aq) (in acidic solution)

In a process, 701 J of heat is absorbed by a system and 394 J ofwork is done by the system. What is the change in internal energy for the process?

What will be the minimum pressure required to compress 500 dm³ of air at 1 bar to 200 dm³ at 30°C?

In a reaction A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures.

(i) 300 atoms of A + 200 molecules of B

(ii) 2 mol A + 3 mol B

(iii) 100 atoms of A + 100 molecules of B

(iv) 5 mol A + 2.5 mol B

(v) 2.5 mol A + 5 mol B

At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?

Which one of the following will have largest number of atoms?

(i) 1 g Au (s)

(ii) 1 g Na (s)

(iii) 1 g Li (s)

(iv) 1 g of Cl2(g)

Density of a gas is found to be 5.46 g/dm³ at 27 °C at 2 bar pressure. What will be its density at STP?

Recently Viewed Questions of Class 11 Chemistry

How would you convert the following compounds into benzene?

(i) Ethyne (ii) Ethene (iii) Hexane

Explain structures of diborane and boric acid.

For the following equilibrium, K_c= 6.3 × 10¹⁴ at 1000 K

NO (g) + O₃ (g) ↔ NO₂ (g) + O₂(g)

Both the forward and reverse reactions in the equilibrium are elementary bimolecular reactions. What is K_c, for the reverse reaction?

Find out the value of K_c for each of the following equilibria from the value of K_p:

(i) 2NOCl (g) ↔ 2NO (g) + Cl₂ (g); Kp = 1.8 × 10^–2 at 500 K

(ii) CaCO₃ (s) ↔ CaO(s) + CO₂(g); Kp = 167 at 1073 K

In a reaction A + B2 → AB2 Identify the limiting reagent, if any, in the following reaction mixtures.

(i) 300 atoms of A + 200 molecules of B

(ii) 2 mol A + 3 mol B

(iii) 100 atoms of A + 100 molecules of B

(iv) 5 mol A + 2.5 mol B

(v) 2.5 mol A + 5 mol B

Find energy of each of the photons which

(i) correspond to light of frequency 3× 1015 Hz.

(ii) have wavelength of 0.50 Å.

Calculate the number of kJ of heat necessary to raise the temperature of 60.0 g of aluminium from 35°C to 55°C. Molar heat capacity of Al is 24 J mol^–1 K^–1.

A liquid is in equilibrium with its vapour in a sealed container at a fixed temperature. The volume of the container is suddenly increased.
a) What is the initial effect of the change on vapour pressure?
b) How do rates of evaporation and condensation change initially?
c) What happens when equilibrium is restored finally and what will be the final vapour pressure?

Calculate the amount of carbon dioxide that could be produced when

(i) 1 mole of carbon is burnt in air.

(ii) 1 mole of carbon is burnt in 16 g of dioxygen.

(iii) 2 moles of carbon are burnt in 16 g of dioxygen.

While sulphur dioxide and hydrogen peroxide can act as oxidising as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants. Why?

Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

Read the question carefully and focus on the core concept being asked.
Reference examples and data from the chapter when answering questions about Chemical Bonding and Molecular Structure.
Review previous year question papers to get an idea of how such questions may be framed in exams.
Practice answering questions within the time limit to improve your speed and accuracy.
Discuss your answers with your teachers or peers to get feedback and improve your understanding.

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