Course Code: BCHCT-131

Assignment Code: BCHCT-131/TMA/2023

Maximum Marks: 100

Note: Attempt all questions. The marks for each question are indicated against it.

\section{PART-(A)}

1. Derive the following expression for the energy of electron in the \(n^{\text {th }}\) orbit.

\(E_{n}=\frac{-Z^{2} e^{2} m}{8 \varepsilon_{o} h^{2} n^{2}}\)

2. What is a black body? Discuss the important features of black body radiation giving a suitable diagram.

3. Derive the time independent Schrodinger equation for a particle.

4. Draw the shapes of \(5 d\) orbitals. Also indicate the signs of wave functions and nodal planes in the diagram.

5. Write the electronic configurations for the following elements.

(i) \(\mathrm{Cr}\)

(ii) \(\mathrm{Mo}\)

(iii) \(\mathrm{Ag}\)

Also explain your answer.

6. (a) Write down Born-Haber cycle for \(\mathrm{CaCl}_{2}\) formation.

(b) Discuss the factors which affect the solubilities of ionic solids in water.

7. Write the assumptions of calculating the formal charge in a molecule. Calculate the formal charge in \(\mathrm{CH}_{3}-\mathrm{C}=\mathrm{O}-\mathrm{CH}_{3}\).

8. Draw the resonance structures of \(\mathrm{HCl}\). Out of them which one has little importance as a resonance structure and why?

9. (a) Calculate the percentage ionic character in \(\mathrm{HBr}\) gas.

Use following data:

The dipole moment of \(\mathrm{HBr}=2.635 \times 10^{-30} \mathrm{C} \mathrm{m}\)

Bond length of \(\mathrm{HBr}=141 \mathrm{pm}\).

(b) An anion will be more easily polarized, if it is large and highly negatively charged. Explain using suitable examples.

10. Draw and explain the molecular orbitals formed by the linear combination of following atomic orbitals

(i) \(p_{\mathrm{x}}\) and \(p_{\mathrm{x}}\) orbitals

(ii) \(p_{\mathrm{y}}\) and \(p_{\mathrm{y}}\) orbitals 11. Explain the following giving suitable examples:

(i) Position isomerism

(ii) Functional group isomerism

(iii) Chiral centre

12. (a) Write two more Fischer projection formulas for the following compound:

(b) Write the enantiomer of the following compound and assign their configurations as \(R\) or \(S\)

13. Draw the possible conformations of cyclohexane and explain their relative stability.

14. (a) Arrange the following compounds in the increasing order of their acidities and give reason in support of your answer.

3-chlorobutanoic acid, butanoic acid, 4-chlorobutanoic acid and 2-chlorobutanoic.

(b) Write acid the resonance structures of propanoate ion.

15. What is \(\mathrm{p} K_{\mathrm{a}}\) ? How does it help in explaining the basicity of different nucleophiles? Write a nucleophilic reaction indicating the nucleophile and its conjugate acid.

16. (a) How would you prepare cyclopentane starting from barium adipate? Write the reactions involved.

(b) Explain the term pyrolysis and cracking giving suitable examples.

17. (a) Explain Saytzeff rule giving a suitable example.

(b) Explain the mechanism of Birch reduction.

18. (a) How would you prepare 2-propanol from propene? Write the steps involved in the conversion.

(b) Write the products of ozonolysis of 2-methyl-2-butene.

19. Give the mechanism of hydration of ethyne and the product form.

20. Giving suitable diagrams, explain the structure of benzene.