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प्रश्न
Is it true that under certain conditions, Mg can reduce SiO2 and Si can reduce MgO? What are those conditions?
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उत्तर
\[\ce{Mg_{(s)} + \frac{1}{2} O2_{(g)} -> MgO_{(s)}[\Delta G_{Mg, MgO}]}\]
\[\ce{Si_{(s)} + O2_{(g)} -> SiO2_{(s)} [\Delta G_{Si,SiO_2}]}\]
The temperature range in which \[\ce{[\Delta G_{Mg,MgO}]}\] is lesser than \[\ce{[\Delta G_{Si,SiO_2}]}\], Mg can reduce SiO2 to Si.
\[\ce{2Mg + SiO2 -> 2MgO + Si}\]; ΔG° = −ve
On the other hand, the temperatures range in which \[\ce{[\Delta G_{Si,SiO_2}]}\] is less than \[\ce{[\Delta G_{Mg,MgO}]}\], Si can be reduce MgO to Mg.
\[\ce{SiO2 + 2Mg -> SiO2 + 2Mg}\]; ΔG° = −ve
The temperature at which ΔfG curves of these two substances intersect is 1966 K. Thus, at temperatures less than 1966 K, Mg can reduce SiO2 and above 1966 K, Si can reduce MgO.
संबंधित प्रश्न
Write down the reactions taking place in different zones in the blast furnace during the extraction of iron.
The impurity that is added externally to remove the impurity already present in the ore is known as ____________.
Choose the correct option of temperature at which carbon reduces \[\ce{FeO}\] to iron and produces \[\ce{CO}\].
For the reduction of \[\ce{FeO}\] at the temperature corresponding to point D, which of the following statements is correct?
For the metallurgical process of which of the ores calcined ore can be reduced by carbon?
(i) Haematite
(ii) Calamine
(iii) Iron pyrites
(iv) Sphalerite
Wrought iron is the purest form of iron. Write a reaction used for the preparation of wrought iron from cast iron. How can the impurities of sulphur, silicon and phosphorus be removed from cast iron?
How is copper extracted from low grade copper ores?
The purest form of iron is prepared by oxidising impurities from cast iron in a reverberatory furnace. Which iron ore is used to line the furnace? Explain by giving reaction.
The mixture of compounds A and B is passed through a column of \[\ce{Al2O3}\] by using alcohol as eluant. Compound A is eluted in preference to compound B. Which of the compounds A or B, is more readily adsorbed on the column?
Why is sulphide ore of copper heated in a furnace after mixing with silica?
Explain the following:
\[\ce{CO2}\] is a better reducing agent below 710 K whereas \[\ce{CO}\] is a better reducing agent above 710 K.
Explain the following:
Generally sulphide ores are converted into oxides before reduction.
Explain the following:
Carbon and hydrogen are not used as reducing agents at high temperatures.
A cuprous ore among the following is:-
Heating of MgCl2 6H2O in absence of HCl gives ______.
Carbon deposition reaction taking place in ______.
Assertion: For the extraction of iron, haematite ore is used.
Reason: Haematite is a carbonate ore of iron.
\[\ce{Au + CN^- + H2O + O2 -> [Au(CN)2]^- + OH^-}\]
The number of CN− ions involved in the balanced equation is ______.
