Advertisements
Advertisements
प्रश्न
Define roasting.
Advertisements
उत्तर
Roasting is the process of heating concentrated ore to a high temperature in the presence of air. The process is usually carried out for sulphide ores.
संबंधित प्रश्न
In the extraction of aluminium: Name the process of concentration of bauxite.
Name the most abundant metal in the earth’s crust.
Name a reducing agent that may be used to obtain manganese from manganese dioxide.
Why does a new aluminium vessel lose shine so soon after use?
Name one metal which is extracted by:
Reduction with heat alone.
How is manganese extracted from manganese dioxide, MnO2? Explain with the help of an equation.
Define the term mineral.
Name one ore of copper (other than cuprite). Which compound of copper is present in this ore? Also, write its chemical formula.
Name the gas produced when calamine ore is calcined.
What is the difference between a mineral and an ore?
How is sodium metal extracted? Explain with the help of equation of the reaction involved.
Give the name of one ore of iron. Which iron compound is present in this ore? Write its chemical formula.
The metal which is always present in an amalgam is ______.
Aluminum is used in thermite welding:
what is thermit?
Aluminum is used in thermite welding:
write reaction for process?
Give the chemical formula of :
Bauxite
Complete the incomplete statement with missing word:
Metals form positive ions while non- metals ______.
State the property of the metal being utilized in the following :
| Use of metal | Property |
| Zinc in Galvanization | |
| Aluminium in Thermite welding |
Answer the following question :
What is the difference between calcination and roasting.
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as ______.
Bauxite reacts with sodium hydroxide in the Bayer’s process.
Explain Bayer’s process.
Oxides of moderately reactive metals like Zinc, Iron, Nickel, Tin, Copper, etc. are reduced by using:
Which of the following metals exist in their native state in nature?
(i) Cu
(ii) Au
(iii) Zn
(iv) Ag
An alloy is
On the basis of reactivity metals are grouped into three categories:
- Metals of low reactivity
- Metals of medium reactivity
- Metals of high reactivity
Therefore metals are extracted in pure form from their ores on the basis of their chemical properties.
Metals of high reactivity are extracted from their ores by electrolysis of the molten ore.
Metals of low reactivity are extracted from their sulphide ores, which are converted into their oxides. The oxides of these metals are reduced to metals by simple heating.
(a) Name the process of reduction used for a metal that gives vigorous reaction with air and water both.
(b) Carbon cannot be used as a reducing agent to obtain aluminium from its oxide? Why?
(c) Describe briefly the method to obtain mercury from cinnabar. Write the chemical equation for the reactions involved in the process.
OR
(c) Differentiate between roasting and calcination giving chemical equation for each.
Assertion (A): The extraction of metals from their sulphide ores cannot take place without roasting the ore.
Reason (R): Roasting converts sulphide ores directly into metals.
A mineral from which the metal can be extracted economically and conveniently is known as ______.
