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प्रश्न
Write the principle behind the following methods of refining:
Hydraulic washing
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उत्तर
The principle behind the given methods of refining are:
i) Hydraulic Washing:
This method is based on difference of gravity between ores and gangue. An upward stream of water is used to wash the powdered ore. The lighter gangue particles are washed away, leaving behind the heavier ones.
ii) Vapour-phase refining:
Vapour-phase refining is the process of refining metal by converting it into its volatile compound and then, decomposing it to obtain a pure metal. To carry out this process,
(i) the metal should form a volatile compound with an available reagent.
(ii) the volatile compound should be easily decomposable, so that the metal can be easily recovered. This method is used for refining nickel, zirconium and titanium.
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\[\ce{A(g) + 2B(g) -> 2C(g)}\]
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| Experiment | Initial concentration of [A]/mol L–¹ |
Initial concentration of [B]/mol L–¹ |
Initial rate of formation of [C]/mol L–¹ s–¹ |
| 1. | 0.30 | 0.30 | 0.10 |
| 2. | 0.30 | 0.60 | 0.40 |
| 3. | 0.60 | 0.30 | 0.20 |
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(i) only one reacting species is involved in the rate determining step.
(ii) the order and the molecularity of slowest step are equal to one.
(iii) the molecularity of the reaction is one and order is zero.
(iv) both molecularity and order of the reaction are one.
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For a chemical reaction starting with some initial concentration of reactant At as a function of time (t) is given by the equation,
`1/("A"_"t"^4) = 2 + 1.5 xx 10^-3` t
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[Given: [At] in M and t in sec.]
[Express your answer in terms of 10-2 M /s]
[Round off your answer if required]
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[ΔH of the reaction = +180.7 kJ mol−1]
- higher temperature
- lower temperature
- higher concentration of N2
- higher concentration of O2
Choose the correct answer from the options given below:
