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प्रश्न
Which one of the following is not true of metal :
Metals are good conductors of electricity.
विकल्प
True
False
उत्तर
Metals are good conductors of electricity. - True
APPEARS IN
संबंधित प्रश्न
Name two metals which are found in nature in the free state.
Name the gas in air which tarnishes silver articles slowly.
Explain giving one example, how highly reactive metals (which are high up in the reactivity series) are extracted.
State why aluminium is extracted from its oxide by electrolysis while copper, lead, iron by reducing agents and mercury and silver by thermal decomposition.
Give the chemical formula of :
Bauxite
Write equations for each of the above metal which reacts with water.
Observe the given figure of reactivity series of metals and answer the following questions:
Reactivity series of metals
- Name two metals which react with water.
- Name two moderately reactive metals.
- Name the most highly reactive metal and the most less reactive metal.
Oxides of moderately reactive metals like Zinc, Iron, Nickel, Tin, Copper, etc. are reduced by using:
- Given below are the steps for extraction of copper from its ore. Write the reaction involved.
- Roasting of copper (I) sulphide
- Reduction of copper (I) oxide with copper (I) sulphide.
- Electrolytic refining
- Draw a neat and well labelled diagram for electrolytic refining of copper
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.
