Nitrogen oxides emitted from the exhaust system of supersonic jet aero
planes slowly deplete the concentration of ozone layer in upper atmosphere.
Comment. [1]
Name the type of potential difference produced between the
fixed charged layer and diffused layer having opposite charges around the colloidal
particle. [1]
Maximum rates attained () for
an enzyme catalysed reaction at different temperature are given below.
t/°C 10 15 20 25
30 35 40 45
1.0 1.7 2.3 2.6 3.2 4.0 2.6 0.2
Comment about the enzyme
activity. [1]
A hydrocarbon does
not react with chlorine in dark but gives a single monochloro compound in
bright sunlight. Identify the hydrocarbon. [2]
Or
Explain why
(i) alkyl halides, though polar, are immiscible with
water?
(ii) Grignard reagents should be prepared under anhydrous
conditions? [1+1]
Explain how you can determine the atomic mass of an
unknown metal if you know its mass density and the dimensions and type of the
unit cell of its crystal? [2]
Explain (i) Why is orthonitrophenol more acidic than orthomethoxy
phenol?
(ii) How does the ?OH group attached to a carbon of
benzene ring activate it towards electrophonic substitution? [1+1]
Account for the following.
(i) of
aniline is more than that of methylamine.
(ii) Although amino group is o-and p-directing in aromatic electrophonic
substitution reactions, aniline on nitration gives a substantial amount of m-nitro
aniline. [2]
Vapour pressure of chloroform () and
dichloromethane ()
at 298K are 200 mm Hg and 415 mm Hg respectively.
(i) Calculate the vapour pressure of the solution prepared
by mixing 25.5 g of and
40 g of at 298
K and
(ii) Mole fractions of each component in vapour
phase. [3]
Or
The vapour pressure of water is 12.3 kPa at 300K.
Calculate vapour pressure of 1 molal solution of a non-volatile solute in
it. [3]
The first order rate constant for the decomposition of
ethyl iodide by the reaction, at
600K is Its
energy of activation is 209 kJ. Calculate the rate
constant of the reaction at 700
K. [3]
(a) Heat of adsorption is greater for chemisorptions than
physisorption. Why?
(b) What is collodion ?
(c) Differentiate between peptization and
coagulation. [3]
(a) Write a non exothermic reaction taking place in the
blast furnace during extraction of iron.
(b) What is flux? What is the role of flux in the
metallurgy of copper?
(c) Although thermo dynamically feasible, in practice,
magnesium metal is not used for the reduction of alumina in the metallurgy of
aluminium. Why? [3]
(i) Which xenon compound is isostructural with ?
(ii) Write the structure of phosphinic acid.
(iii) Write a chemical reaction for the use of phosphoric
acid as a reducing agent. [3]
Write balanced chemical equations for the following
reactions.
(i) Reaction of with
cold and dilute NaOH.
(ii) Thermal decomposition of ammonium dichromate.
(iii) When phosphine is passed through mercuric chloride
solution.
(i) What happens to the colour of coordination compound when
heated gradually?
(ii) Give the electronic configuration of the d-orbitals
of ion
and explain why this complex is coloured? (At. no. of Ti = 22)
(iii) Write IUPAC name of. [3]
(a) (i) Which is stronger reducing agent or and
why?
(ii) Explain why is a
strong oxidising agent?
(iii) Explain why ion
is not stable in aqueous solutions? [3]
(b) Describe the oxidising property of in
neutral or faintly alkaline medium for its reaction with iodide ions and this sulphate
ions. [2]
Or
Account for the following.
(i) Ox anions of a metal show higher oxidation state.
(ii) Oxidising power in the series
(iii) Actinoid contraction is greater from element to
element than lanthanoid contraction.
(b) Silver atom has completely filled d-orbitals (4d10)
in its ground state. How can you say that it is a transition
element? [2]
(a) What type of a battery is lead storage battery? Write
the anode and cathode reactions and the overall cell reaction occurring in the
operation of a lead storage battery.
(b) Calculate the potential for half-cell containing (ag), and (ag) The
half-cell reaction isand
the standard electrode potential is given as E° = 1.33 V. [2+3]
Or
(a) How many moles of mercury will be produced by
electrolyzing solution
with a current of 2.00 A for 3 hours?
(b) A voltaic cell is set up at 25°C with the following
half-cells (0.001
M) and (0.50M).
Write an equation for the reaction that occurs when the cell generates an electric
current and determine the cell potential. (Given,)
[2+3]
(a) Write chemical equations to illustrate the following name bearing reactions.
(i) Cannizzaro reaction (ii) Hell-Volhard-Zelinsky reaction
(b) Give chemical tests to distinguish between the following pairs of the compounds.
(i) Propanal and propanone (ii) Acetophenone and benzophenone
(iii) Phenol and benzoic acid [2+3]
Or
(a) How will you bring about the following conversions?
(i) Ethanol to 3-hydroxy butanal (ii) Benzaldehyde to benzophenone
(b) An organic compound 'A' has the molecular formula It get hydrolyzed with dilute sulphuric acid and gives a carboxylic acid 'B' and an alcohol 'C' oxidation of 'C' with chromic acid also produced 'B'. 'C' on dehydration reaction gives but-1-ene. Write equations for the reactions involved. [2 + 3]