BCHCT-131 : ATOMIC STRUCTURE, BONDING, GENERAL ORGANIC CHEMISTRY AND ALIPHATIC HYDROCARBONS
Time : 2 hours Maximum Marks : 50
Note : (i) Attempt any five questions from Part A and any five questions from Part B on separate answer sheets. (ii) All questions carry equal marks.
PART A (Maximum Marks : 25)
1. (a) Discuss the contribution of Rutherford in explaining the structure of an atom. 3 (b) Which of the following molecules has a dipole moment, CH4 or NH3 ? Give reason. 1 (c) Name the force by which the molecules are held together in the crystal structure of a compound.
2. (a) Why is oxygen paramagnetic ? Explain using molecular orbital theory.
3 (b) State the type of hybridisation present in benzene and SF4 molecules. 2
3. (a) Write the steps used in valence bond method to arrive at the structure of a molecule.
3 (b) Classify the following statements as true or false. Also give reason in support of your answer. 2
(i) Ionisation energy of sodium is less than that of magnesium.
(ii) First ionisation energy of magnesium is more than its second ionisation energy.
4. (a) Write all steps to obtain the Lewis structure of CO2 . 3
(b) Briefly explain the photoelectric effect. How did Einstein explain it ? 2
5. Name the four quantum numbers of an electron and give their significance. What is Pauli’s Exclusion Principle ? 5
. 6. (a) Explain the difference between a covalent and a coordinate covalent bond with a suitable example. 3 (b) Write the electronic configurations of Cr (At. No. = 24) and Ag (At. No. = 47). 2 7. (a) Explain the significance of and 2 .
(b) Give the characteristics of a well-behaved wave function. Draw a suitable diagram for the well-behaved wave function. 3
PART B (Maximum Marks : 25)
8. (a) What is the product of Kolbe’s electrolysis of sodium acetate ? Write the reaction and its mechanism. 3
(b) How will you convert 2-pentyne to cis and trans-2-pentene ? 2
9. (a) Write the products of oxidative ozonolysis of 2-methyl-2-butene. 2
(b) Arrange the following compounds in the increasing order of their acidity and give reason for answer : 3 CH3CHCH2COOH, CH3CH2CHCOOH, | | Cl Cl ClCH2CH2CH2COOH
10. (a) Which one of the following compounds will exibit optical activity and why ? OH
| (i) CH3CHCOOH (ii) HOOC(CH2 ) 2COOH Draw two Fischer projections of compound (i). 3
(b) How will you prepare 1-hexyne from ethyne ? 2
11. What are electrophiles and nucleophiles ? Give one example each of
(i) a neutral electrophile
, (ii) a neutral nucleophile, and
(iii) a charged electrophile. 5
12. (a) Explain Saytzeff’s rule with the help of a suitable example. 3
(b) Write the products formed by the reaction of HBr and propene when
(i) no peroxide is present, and (ii) in the presence of peroxide. 2
13. (a) Draw the conformations of cyclohexane. Comment on their relative stabilities. 3
(b) How are straight chain alkanes converted to branched chain alkanes ? What is the importance of this reaction ?
