Long Answer Type(i) Write the equation which relates the number of phases, components and degree of freedom of a system in equilibrium.
(ii) How many phases and components are there in a system consisting of:
(1) a mixture of O2 and N2 gases
(2) N2 gas containing H2O vapour
(3) a mixture of ice and water
(4) a mixture of powdered iron and sulphur
(5) a lump of solid iron (II) sulphide
Give a suitable explanation, in brief, for your answer.
Consider the reaction,
A + B → C + D
The initial rates for different initial concentrations of the reactants are given below :
Initial concentration (mol 1– 1Initial rate (mol 1 –1 s– 1)
|
A |
B |
||
|
(i) |
1.0 |
1.0 |
2.0 x 10 – 3 |
|
(ii) |
2.0 |
1.0 |
4.0 x 10– 3 |
|
(iii) |
4.0 |
1.0 |
8.0 x 10– 3 |
|
(iv) |
1.0 |
2.0 |
2.0 x 10– 3 |
|
(v) |
1.0 |
4.0 |
2.0 x 10’3 |
(a) What are the orders with respect to A and B ?
(b) What is the overall order ?
(c) Write the rate law equation.
(d) Calculate the rate constant.
(e) Suggest a possible mechanism.
According to equation A+B --> C +D
The initial rates is given by [A]m[B]n
(i) Initial rate = k[1]m[1]n =2.0 x 10-3
ii) Initial rate = k[2]m[1]n = 4.0 x 10-3
iii) Initial rate = k[4]m[1]n = 8.0 x 10-3
iv) Initial rate = k[1]m[2]n = 2.0 x 10-3
v) Initial rate = k[2]m[4]n = 2.0 x 10-3
a) 
Explain the principle involved in the following observations :
(i) Cu2+ is precipitated as CuS in the acidic medium while Ni2+ is precipitated as NiS in a basic medium with H2S.
(ii) A solution of a weak acid and its salt with strong base has a definite pH value which does not change appreciably on dilution.
(iii) A solution of sodium chloride is neutral while that of ferric chloride is acidic in nature.
(i) Why could fluorine not be prepared for a long time from HF and metal fluorides either by electrolysis or by any chemical reaction ?
(ii) Describe the modern method for the preparation of fluorine by giving :
(a) Materials used in the construction of the cell.
(b) Electrolyte used.
(c) Electrode reactions.
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