JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech I Year CHEMISTRY Previous Question Paper (January - 2021 - R18)
Answer any five questions. All questions carry equal marks.
Main
Draw molecular orbital energy level diagram for oxygen molecule. Calculate bond order and write its magnetic behaviour.
Answer
The molecular orbital (MO) configuration for the oxygen molecule (O2) with 16 electrons is: (σ1s)2 (σ*1s)2 (σ2s)2 (σ*2s)2 (σ2pz)2 (π2px)2 (π2py)2 (π*2px)1 (π*2py)1.
Substituting the values: Bond Order = (10 - 6) / 2 = 2. The molecule has two unpaired electrons in the antibonding π* orbitals, which makes it paramagnetic.
Write salient features of crystal field theory. Explain crystal field splitting of transition metal ‘d’ orbitals in octahedral field.
Answer
The salient features of Crystal Field Theory (CFT) are:
- Ligands are treated as point charges (anions) or dipoles (neutral molecules).
- The bond between the metal and ligand is purely electrostatic.
- In an isolated metal ion, all five d-orbitals are degenerate (equal energy).
- When ligands approach, the degeneracy is lifted due to electrostatic repulsion, causing d-orbital splitting.
In an octahedral field, six ligands approach along the x, y, and z axes. The dx2-y2 and dz2 orbitals (eg set) point directly at the ligands, experiencing greater repulsion and higher energy. The dxy, dyz, and dzx orbitals (t2g set) point between the axes, experiencing less repulsion and lower energy. The energy difference between these two sets is denoted as Δo (crystal field splitting energy).
What are the causes and effects of hard water? What are the units in which hardness of water is Expressed? Name the methods for the removal of temporary and permanent hardness of water?
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Give an account on ion-exchange process. How exhausted resins are regenerated?
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Differentiate primary and secondary batteries. How do you construct Lithium primary battery?
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Explain about cathodic protection methods by sacrificial anodic and impressed cathodic protection methods.
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Discuss about conformational analysis of n- butane.
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How do you synthesise Paracetamol and give its pharmaceutical applications.
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Write the selection rules applicable to UV spectroscopy.
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How IR spectroscopy is used to identify the following functional groups – OH, >CO, -CHO, -NH2.
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Differentiate atomic and molecular orbitals. How does doping effects conduction in solids?
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Give an account on pi molecular orbitals of butadiene.
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Describe the steps involved in the treatment of potable water.
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Derive Nernst equation for electrode potential.
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Differentiate enantiomers and diastereomers with suitable examples.
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What are SN1 and SN2 reactions? Give one example for each type. Describe Walden inversion.
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