(i) Why are haloalkanes more reactive towards nucleophilic
substitution reactions than haloarenes?
(ii) Which one of the following two substances undergoes Syl
reaction faster and why?
Or
Write the structures and names of the compounds formed
when compound A with molecular formula is
treated with the
presence of .
[2]
Aspirin and phenacetin are analgesics. Aspirin is pain reliever.
It was never used alone but it had been used in APC tablets (combination of
aspirin, phenacetin and caffeine) for curing common cough and. cold.
The use of phenacetin was claimed to produce a sense of
relaxation, to reduce tension and to increase work capacity. It was considered
to be habit forming, overdose ofwhich may lead to kidney damage.
Answer the following question based on the above passage-
Identify A to E in the synthesis of E (phenacetin).
[2]
Two half reactions of an electrochemical cell are given
below
Construct
the redox equation from the standard potential of the cell and predict if the reaction
is reactsnt favoured or product favoured.
[2]
A sample of iron (II) oxide has actual formula. In
this sample what fraction of metal ions are ions?
What type of non-stoichiometric defect is present in this sample?
Or
Niobium crystallises in body csnered cubic structure. If
density is 8.55 .
Calculate the atomic radius of niobium using its atomic mass 93 u. [3]
How do antiseptics differ from disinfectants? Give one
example of each. Name a substance which can be used as an antiseptic as well. as
disinfectant, [3]
(a) The chemistry of corrosion of iron is essentially an
electrochemical phenomenon.
Explain the reactions occurring during the corrosion of
iron in the atmosphere.
(b) Express the relation between conductivity and molar conductivity
of a solution held in a
cell.
(i) What is the basicity of phosphorous acid and why?
(ii) fumes
in moist air. Explain.
(iii) In preparation of fluorine by electrolysis of anode
and cathode are kept separated by a diaphragm of teflon. Why?
Explain the following observations.
(i) Why are powders substance more effective adsorbents
than crystalline forms?
(ii) Why is ester hydrolysis slow in the beginning but
becomes faster after some time?
(iii) What happens when Fe(OH)3 sol is mixed
with
(i) Justify the formation of a low spin complex and a high
spin complex taking the examples of andon the
basis of '' crystal field splitting energy''.
(ii) Write the IUPAC name of
Explain the following observations.
(i) Many of the transition elements are known to form
interstitial compounds.
(i) There is general increase in density from titanium (Z
=22) to copper (Z =29).
(iii) The members of the actinide series exhibit a larger
number of oxidation states than the corresponding members of the lanthanide
series. [3
x 1]
Explain the following observations.
(i) Nitrogen is much less reactive than phosphorus.
(ii) Despite having greater polarity, hydrogen fluoride
boils at a lower temperature than water.
(iii) Sulphur has greater tendency for catenation than
oxygen in the same group.
(b) Draw the structures of the following molecules.
(i) (ii) [3
+ 2]
Or
(a) Explain the following observations.
(i)is more
acidic than
(ii) Fluorine does not exhibit any positive oxidation
state.
(iii) Helium forms no real chemical compound.
(b) Draw the structures of the following molecules.
(i)
(ii) [3
+ 2 ]
An organic compound (A) with molecular formula forms
an orange red precipitate with 2, 4-DNP reagent and gives yellow precipitate on
heating with iodine in the presence of sodium hydroxide. It neither reduces
Tollen's or Fehling's reagent, nor does it decolorize bromine water or Baeyer's
reagent. On drastic oxidation with chromic acid, it gives a carboxylic acid (B)
having molecular formula .
Identify the compounds (A) and (5) and explain the reactions involved.
[3]
(b) Write chemical reactions to affect the following
transformations.
(i) Cyclohexene to adipic acid.
(ii) 3-bromonitrobenzene to 3-nitrobenzoic
acid. [2]
Or
(a) Write down the functional isomers of a carbonyl
compound with molecular formula . Which
isomer will react faster with HCN and why ? Explain the mechanism of the
reaction also. Will reaction lead to the completion with the conversion of
whole reactant into product at reaction conditions. If a strong acid is added
to the reaction mixture what will be the affect on concentration of the product
and why? [3]
(b) Arrange the following in decreasing order of their
acidic strength and give reason
for your answer.
Express clearly what you understand by 'rate expression'
and 'rate constant' of a reaction? [2]
(b) Nitrogen pent oxide decomposes according to the
equation
This first order reaction was allowed to proceed at 40°C
and the data given below were collected.
Time (min)
0.400
0.289
0.209
0.151
0.109
0.00
20.00
40.00
60.00
80.00
(i) Calculate the rate constant for the reaction. Include
units with your answer.
(ii) Calculate the initial rate of reaction.
(iii) After how many minutes will be
equal to 0.350 M? [3]
Or
(a) Define
(i)Order of a reaction (ii)
Elementary step in a reaction. [2]
(b) A first order reaction has a rate constant value of 0.005 . If we
begin with 0.10 M concentration of the reactant, how much of the reactant will
remain after 3.0
hours? [3]