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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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संबंधित प्रश्न
For the first order thermal decomposition reaction, the following data were obtained:
Time / sec Totalpressure / atm
0 0.30
300 0.50
Calculate the rate constant
(Given: log 2 = 0.301, log3 = 0.4771, log 4 = 0.6021)
From the rate expression for the following reaction, determine the order of reaction and the dimension of the rate constant.
\[\ce{3NO_{(g)} -> N2O_{(g)}}\] Rate = k[NO]2
For a complex reaction:
(i) order of overall reaction is same as molecularity of the slowest step.
(ii) order of overall reaction is less than the molecularity of the slowest step.
(iii) order of overall reaction is greater than molecularity of the slowest step.
(iv) molecularity of the slowest step is never zero or non interger.
Assertion: Order and molecularity are same.
Reason: Order is determined experimentally and molecularity is the sum of the stoichiometric coefficient of rate determining elementary step.
Assertion: The enthalpy of reaction remains constant in the presence of a catalyst.
Reason: A catalyst participating in the reaction, forms different activated complex and lowers down the activation energy but the difference in energy of reactant and product remains the same.
If the 0.05 molar solution of m+ is replaced by a 0.0025 molar m+ solution, then the magnitude of the cell potential would be
The half-life period of a. substance in a certain enzyme catalysed reaction is 138 s. The time required for the concentration of the substance to fall from 1.28 mol–1 to 0.04 mg L–1 is
The conversion of molecules A to B follow second order kinetics. If concentration of A is increased to three times, how will it affect the rate of formation of B?
Which of the following statement is true?
Higher yield of NO in \[\ce{N2(g) + O2 <=> 2NO(g)}\] can be obtained at:
[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:
