Download OU (Osmania University) B.Sc Life Sciences 5th Sem Chemistry Important Question Bank For 2021 Exam
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QUESTION BAN
B.Sc III Year CHEMISTRY - 5
SEMESTER- V
Unit-I Inorganic Chemistry
Chap-1- COORDINATION COMPOUNDS-II
Short answer questions:
1. Explain the magnetic behaviour of Ti4+ and Cu2+ ion on the basis of
electronic configuration.?
2. Briefly explain inetic stability of a complex compounds?
3. Give an example of bridge ligand and write its IUPAC name?
4. Distinguish between diamagnetism and paramagnetism?
5. How the magnetic properties are helpful in nowing the number of
unpaired
electrons in an atom of an element?
6. Cupric salts are blue coloured while cuprous salts are colourless. Why?
7. Discuss the steric effect and the bacbonding effect of ligands which
decide the stability of a metal complex?
8. How will you determine the composition of a complex by job's method.
Write the limitations of this method ?
Long Answer Questions:
1. What is meant by crystal field splitting ? Describe the splitting of d-
orbitals in octahedral , tetrahedral and square planar field ?
2. The complexex formed by chelating ligands are more stable than their
monodentate analogs.Explain with suitable examples ?
3. a) Give the spectra of [Ti(H2O)6]3+ . Explain ?
b) Give Gouy's method for determining the magnetic susceptibility ?
4. Discuss the formation of coordination compounds on the basis of inetics
stability concept ?
5. What do you understand by the term stability constant ? Mention the
various factors that effect the stability constant of a complex ion ?
6. a) What are inert and labile complexes ? Discuss inetically inert but
thermodynamically stable complexes ?
b) What is the difference between thermodynamically stable and
inetically inert complexes ?
7. What is meant by crystal field theory ? What are the postulates of crystal
field theory ?
Chap-2- BORANES AND CARBORANES
SHORT ANSWER QUESTIONS:
1. Define the terms
a) Clusture
b) Boranes
c) Carboranes
2. Write a short note on Wade's Rule ?
3. Give a brief account of bonding in boranes ?
4. Write the structures of
i) Closo
ii) Nido-carborane
iii) Monocarboranes
LONG ANSWER QUESTIONS:
1. Draw and explain the structure of tetraborane (B4H10) ?
2. Explain the structure of Hexaborane ?
3. Explain the structure of pentaborane ?
4. Explain the following with examples.
i) Diborane
ii) Carboranes
UNIT-II ORGANIC CHEMISTRY
Chap-1- AMINES, CYANIDES AND ISOCYANIDES
SHORT ANSWER QUESTIONS:
1. Write the classification of amines with examples. Give two examples of
diamines ?
2. Explain Gabriel Phthalimide reaction ?
3. Give the nucleophilic substitution reactions of nitrobenzene ?
4. Write a note on the basic character of amines ?
5. How aniline reacts with :
i) Picric acid
ii) Acetyl chloride
iii) Chloroform and OH
6. Give the mechanism of the nitration of Benzene ?
7. Write reactions to distinguish between primary, secondary and tertiary
amines ?
8. Write a note on Hofmann elimination ?
9. Write the mechanism of Hofmann bromamide reaction ?
10. Write the methods for the preparation of each of the following :
a) Methyl Cyanide
b) Methyl Isocyanide
11. Write a note on Carbylamine reaction ?
LONG ANSWER QUESTIONS:
1. What is ortho effect ? How does it effect the basicity of aromatic amines?
2. Compare the behaviour of aniline, N-methyl aniline and NN-
Dimethylaniline
towards each of the following :
i) Dil.HCl
ii) NaNO2 + HCl
iii) Acetic anhydride
3. Write the mechanism and the reagents needed in the preparation of the
following :
i) Aniline from Benzamide
ii) Isobutylene from isobutylamine
4. a) Explain the preparation of Benzene diazonium chloride ?
b) Describe the synthetic uses of benzene diazonium chloride ?
5. Write down the chemical equations for the reduction of nitrobenzene with
the following reducing agents.
i) Sn + HCl
ii) Zn + NaOH
iii) Zn - NH4Cl
6. Explain the following :
a) Amine salts as phase transfer catalysts.
b) Libermann's nitroso reaction.
c) Separation of a mixture of primary, secondary and tertiary amines.
7. a) Amines are more basic than alcohols. Explain ?
b) Write the properties and uses of methyl isocyanide ?
8. a) Explain the mechanism of Diazotisation ?
b) Aliphatic amines are more basic than ammonia. Explain ?
c) Describe the synthetic applications of Aryl diazonium salts ?
9. Write a detailed note on cope rearrangement ?
a) Give an example to illustrate cope elemination ?
b) Write structural formula and reaction condition for the following
conversions. i) m-chlorobromo benzene from m-chloroaniline
ii) Bromo benzene from chloro aniline.
10. How are primary aromatic amino compounds prepared ? Starting from
aniline , how would you obtain the following compounds ?
i) Sulphanilic acid
ii) p-Nitroaniline
Chap-2- HETEROCYCLIC COMPOUNDS
SHORT ANSWER QUESTIONS:
1. Define heterocyclic compounds and give their classification ?
2. How do you prepare pyrrole by Paul-norr synthesis ?
3. Give the brief description of pyridine ?
4. Briefly explain the aromaticity of Furan, Thiophene and Pyrrole ?
5. Explain why thiophene is less reactive than pyrrole and furan for
electrophilic substitution reactions ?
6. Give one method of preparation of each of Furan, Thiophene and
pyrrole?
7. Explain, an energy level diagram about the electrophilic substitution of
thiophene and pyrrole ?
LONG ANSWER QUESTIONS:
1. Give any two methods for the synthesis of pyridine ?
2. Explain the following reactions :
i) Pyrrole + CHCl3/NaOH ------->
ii) Thiophene + 3H2 + Ni ( heat) -------->
iii) Furan + Maleic acid ------->
3. Using qualitative test tube experiments,how can the following be
distinguished.
i) Benzene from pyrrole
ii) Furan from thiophene
4. a) Elucidate the structure of Furan.
b) How furan reacts with
i) Pyridine-Sulphur trioxide ii) HCl - HCN
iii) Maleic anhydride iv) Hydrogen in presence of
nicel
5. Give explanations for the following observations :
i) Furan shows a great deal of dienyl character inspite of its aromatic
nature
ii) Pyrrole is a wea acid rather than a strong base
iii) Thiophene is more reactive than benzene towards electrophilic
aromatic
substitutions.
6. a) Give three methods for the synthesis of pyrrole and write its
reactivity.
b) Give two addition reactions in pyrrole.
c) Electrophilic substitution in pyrrole, furan and thiophene occurs
preferentially at 2nd position.
7. Give the valance bond description of furan, thiophene and pyrrole ?
8. By writing the resonating structures , locate the reactive position in
thiophene for electrophilic attac ?
UNIT-III PHYSICAL CHEMISTRY
Chap-1- CHEMICAL INETICS
SHORT ANSWER QUESTIONS:
1. Define rate of reaction. How will you differentiate between the reaction
rate and rate constant ?
2. Give two methods for determining the order of reaction ?
3. How does the collision theory of reaction rates explain the effect of
temperature on the rate constant ? Explain.
4. Draw well lablled energy level diagram for
i) An exothermic reaction
ii) An endothermic reaction
5. Discuss the Arrhenius equation for temperature dependence of reaction
rates. Show how it is possible to obtain the value of activation energy of
a reaction ?
LONG ANSWER QUESTIONS:
1. What is second order reaction ? Deduce an equation giving the velocity
constant of a second order reaction. What are the characteristics of a
second order reaction ?
2. Write a detailed note on activation energy of a reaction ?
3. a) Write the points of difference between order of reaction and
molecularity.
b) How will you proceed to calculate the order as well as the
molecularity of
a complex reaction ? Explain by taing an examples ?
4. Derive an expression for the inetics of the first order reaction ?
5. Discuss the factors which influence the rate of a reaction ?
6. Describe in detail about the collision theory of reaction ?
PROBLEMS:
1. Derive =2.303/t log a/a-x . Explain what is meant by energy of
activation.
A first order reaction is 40% complete in 50 minutes. What is the value
of the rate constant in sec-1 ?
2. Briefly explain the theories of reaction rates. The rate constants of a first
order reaction at 298 and 318 are 1.25 x 10
-4 sec-1 and 8.5 x 10-5 sec-1
respectively. Calculate the activation energy of the reaction ?
3. A second order reaction in which the initial concentration of both
reactants
are same is 25% complete in 600 seconds. How long will it tae for the
reaction to 75% completion ?
4. Calculate the activation energy of a reaction whose rate constant is
tripled
by a 10oC rise in temperature ?
5. In the thermal decomposition of maalonic acid
CH2(COOH)2 -------> CH3COOH + CO2 , the pressure at different time
intervals are :
t (min.) 10 20 35 56 ---
p (mm) 37 67 108 155 303
What is the order of the reaction ?
UNIT-IV GENERAL CHEMISTRY
Chap-1- MOLECULAR SPECTROSCOPY
SHORT ANSWER QUESTIONS:
1. What do you mean by absorption of radiation in the spectrum or a record
?
2. Why is methanol a good solvent for UV and not for IR ?
3. Give a brief account of stretching and bending vibrations which occur in a
compound when exposed to infrared radiations ?
4. Define the term Spectroscopy ? How will you determine the bond length
of a diatomic molecule by Rotational spectroscopy ?
5. What do you mean by electromagnetic spectra ? Enlist the different
types of radiations along with frequency ranges and sources ?
6. Define electronic spectroscopy. What is its range ? Write the relationship
between wavelength, frequency and wave number ?
7. Describe the effect of inter-molecular and intra-molecular hydrogen
bonding on the position of absorption frequency of a compound. Give an
example ?
8. Describe some characteristic absorption bands with their probable region
and intensity for the following functional groups.
a) - OH (alcoholic)
b) Carbonyl group
c) Aromatic compounds
9. a) Explain the term probability.
b) Write the physical significance of molar extinction coefficient.
10. Explain the selection rules for Electronic spectra ?
11. Write the characteristic stretching absorption bands of ethanol and
p-amines ?
12. Explain the Chromophore and Auxochrome concept ?
LONG ANSWER QUESTIONS:
1. Define infra-red spectroscopy ? Describe the various molecular vibrations
in the technique. What is the major requirement for infra-red absorption ?
2. a) Define and explain the laws governing the absorption of light , i.e.
Beer's law and Lambert's law.
b) Describe the limitations of Beer-Lambert law.
3. Give the characteristic absorption of aldehydes and aliphatic amines by
taing one example in each case ?
4. Write a note on the modes of vibrations in diatomic and polyatomic
molecules ?
5. Explain the following by taing examples in each case.
i) Absorption and intensity shifts.
ii) Solvent effects.
iii) Bonding and antibonding molecular orbitals.
6. a) What are absorption law ? How is an ultraviolet spectrum plotted ?
b) Explain quantisation of energy ?
7. Explain the chemistry of electronic spectroscopy ? Give the various
types of transitions involved in this technique with one example in each
case ?
8. a) Write the types of spectrometers. Describe double beam
spectrophotometer in brief.
b) Describe the advantages of double beam spectrophotometer.
9. Give an explanatory account of the energy levels of molecular orbitals
and also write the order of increasing energies of molecular orbitals.
10. Discuss the following statements :
i) Hydrogen bonding raises the wavelength of absorption.
ii) The process of -I effect raises the wave number of absorption.
iii) Conjugation raises the wavelength of absorption of a particular
group.
Chap-2- PHOTOCHEMISTRY
SHORT ANSWER QUESTIONS:
1. Define photochemistry ? What is the difference between photochemical
reactions and thermochemical reactions ?
2. a) Define Beer's law and Lambert's law ?
b) Define and explain the term Quantum efficiency ?
3. Explain Grotthus-Draper principle of photochemical activation ?
4. Write short note on phosphorescence and fluorescence ?
5. What do you understand by primary process in photochemical process
and photochemical equilibrium ?
6. Discuss the photochemistry of hydrogen-bromine reaction ?
7. Discuss the photochemistry of hydrogen-chloride reaction ?
LONG ANSWER QUESTIONS :
1. Define and explain Star-Einstein's law of photochemical equivalence ?
2. Draw a well labelled Jablonsi diagram and explain the following from it.
i) ISC (inter system crossing/conversion)
ii) IC (internal crossing/conversion)
iii) Radiative and non-radiative
iv) spin state
v) Phosphorescence
vi) Fluorescence
3. Define quantum yield. Explain abnormal quantum yields giving atleast
two examples ?
4. Explain the laws of photochemistry i) Lambert's law and ii) Beer's law ?
What are its limitations ?
5. What do you understand by photosensitized reactions and
photosensitization ? Explain .
6. Write notes on :
a) Photosynthesis
b) Luminescence
c) Chemiluminescence
7. Distinguish between the primary and secondary process in a
photochemical reaction ?
8. Define quantum efficiency ? Explain experimental determination of
quantum yield ?
PROBLEMS :
1. Calculate the value of einstein corresponding to radiation of wavelength
6000 Ao ?
2. What is the absorption coefficient of a solution which absorbs 90% of a
certain wavelength of light beam passed through a 1cm cell containing
0.25M solution ?
3. A sample of acetone absorbs monochromatic radiation at the rate of
4.5 x 1020 quanta sec-1. The number of moles of acetone decomposed in
one second is 1.35 x 10-4 . Calculate the quantum yield of photolysis of
acetone ?
4. A certain system absorbs 3 x 1016 quanta of light per second. On
irradiation
for 10 minutes, 0.002 mole of the reactant was found to have reacted.
Calculate the quantum efficiency of the process ?
This post was last modified on 23 January 2021