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प्रश्न
Explain concept with example/explain with the help of a balanced equation.
Ionic bond and ionic compounds
उत्तर
- The compounds formed from two units, namely cation and anion are called ionic compounds.
- The cation and anion being oppositely charged, there is an electrostatic force of attraction between them. This force of attraction between cation and anion is called as the ionic bond.
- The number of cations and anions in a compound and the magnitude of the electric charge on them is such that the positive and negative charges balance each other. As a result, an ionic compound is electrically neutral.
- For example, ionic compound sodium chloride (NaCl) is formed as sodium metal gives away one electron while the nonmetal chlorine takes up one electron. Na+ and Cl− ions formed are held together by attractive force called ionic bond.
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संबंधित प्रश्न
Silver metal does not combine easily with oxygen but silver jewellery tarnishes after some time. How?
Write the composition of the alloy called bronze.
Name three other metals which are extracted in a manner similar to sodium.
Name two ores of zinc. Write the names of the chemical compounds present in them and give their chemical formulae.
The major ore of aluminium is known as:
(a) cinnabar
(b) calamine
(c) bauxite
(d) pyrolusite
The metal which can be extracted from pyrolusite ore is:
(a) mercury
(b) manganese
(c) aluminium
(d) magnesium
A metal which exists as a liquid at room temperature is obtained by heating its sulphide ore in the presence of air.
(a) Name the metal and write its chemical symbol.
(b) Write the name and formula of the sulphide ore.
(c) Give the equations of chemical reactions involved in the production of metal from its sulphide ore.
(d) Name a common device in which this metal is used.
(e) Can this metal displace copper from copper sulphate solution? Why?
State three objectives achieved during the roasting of ores.
Give the principles of electromagnetic separation.
Give reasons, why aluminum is used in:
making alloys
Write equations for each of the above metal which reacts with water.
Name a non- metal that has a metallic luster and sublimes on heating.
Extraction of moderately reactive elements is done by _______ and _______ method.
Zinc sulphide : Roasting : : zinc carbonate : _______
The electrolysis of alumina involves the use of fluorspar and cryolite to increase the melting point.
Gold and silver are active metals.
Explain the reactions of nonmetals with water with the help of examples.
The process in which a carbonate ore is heated strongly in the absence of air to convert it into metal oxide is called ____________.
Oxides of moderately reactive metals like Zinc, Iron, Nickel, Tin, Copper, etc. are reduced by using:
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.
