Advertisements
Advertisements
प्रश्न
Explain concept with example/explain with the help of a balanced equation.
Roasting
उत्तर
- The process of heating of sulphide ores strongly in excess of air to convert it into respective oxide is called roasting.
- For example, zinc sulphide is heated strongly in excess of air to convert it to zinc oxide.
\[\ce{\underset{\text{Zinc sulphide}}{2ZnS_{(s)}} + 3O_{2(g)} -> \underset{\text{Zinc oxide}}{2ZnO_{(s)}} + \underset{\text{Sulphur dioxide}}{2SO_2↑}}\]
APPEARS IN
संबंधित प्रश्न
M is a metal above hydrogen in the activity series and its oxide has the formula M2O. This oxide when dissolved in water forms the corresponding hydroxide which is a good conductor of electricity. In the above context, answer the following:
1) What kind of combination exists between M and O?
2)How many electrons are there in the outermost shell of M?
3) Name the group to which M belongs.
4) State the reaction taking place at the cathode.
5) Name the product at the anode.
Name the most abundant metal in the earth's crust.
Write the composition of the alloy called bronze.
Why do gold ornaments look new even after several years of use?
Why are the metals like Na, K, Ca and Mg never found in their free state in nature?
Name one ore of copper (other than cuprite). Which compound of copper is present in this ore? Also, write its chemical formula.
Name the chemical compound which is electrolysed in molten state to obtain aluminium metal. Which gas is evolved during this process?
Name three other metals which are extracted in a manner similar to sodium.
Which of the following metals are extracted by the electrolysis of their molten chlorides?
(a) Na and Hg
(b) Hg and Mg
(c) Na and Mg
(d) Cu and Fe
The articles made of silver metal become dark on prolonged exposure to air. This is due to the formation of a layer of its:
(a) oxide
(b) hydride
(c) sulphide
(d) carbonate
Name the following:
The substance added to get rid of gangue in the extraction of metal.
Name the following:
The process in which an ore is heated in air so that oxygen gets added to it to form the oxides.
Which method of refining is used to get 99.8% pure aluminium?
Which one of the following is not true of metal :
Metals are malleable and ductile
Which one of the following is not true of metal :
Metals form non-polar covalent compounds
Atomic number of aluminium is _______ and its electronic configuration is _______.
Zinc sulphide : Roasting : : zinc carbonate : _______
Explain Bayer’s process.
Read the following passage and answer the questions.
According to the reactivity series, zinc is more reactive than iron, iron is more reactive than silver. During study of this, a student dipped the iron nails in silver nitrate solution.
- What is reactivity series?
- What will happen when iron nails are dipped in silver nitrate solution?
- Which type of reaction happens when iron metal reacts with silver nitrate solution?
- What will happen if a zinc rod is used instead of iron nail?
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.
