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Choose a metal out of the following which reacts with hot water but not with cold water : Sodium, Magnesium, Iron
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1
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2219
|
March 29, 2019
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What is an alloy? Name the constituents of 22-carat gold. Why is 24-carat gold converted to 22-carat gold?
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1
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2014
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March 29, 2019
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Why does magnesium powder reacts much more rapidly than magnesium ribbon with dilute sulphuric acid?
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1
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1644
|
March 29, 2019
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Name any two non-metals which are used in industry. How is each one of them important to us
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1
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1325
|
March 29, 2019
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A solution of copper sulphate was kept in an iron pot. After a few days, the iron pot
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1
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8698
|
March 29, 2019
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What is the valency of silicon with a atomic number 14?
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1
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1579
|
March 29, 2019
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What is seen to happen when a piece of sodium metal is dropped into water?
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1
|
516
|
March 29, 2019
|
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Why do metals not evolve hydrogen gas with nitric acid?
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1
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2650
|
December 27, 2018
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How do you classify elements into metals and non-metals on the basis of their electronic configuration?
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0
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12263
|
March 18, 2018
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Distinguish between ‘roasting’ and ‘calcination’. Which of these two is used for sulphide ores and why?
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0
|
5577
|
March 18, 2018
|
|
Distinguish between ionic and covalent compounds under the following properties
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0
|
9549
|
March 18, 2018
|
|
What is an ionic bond?
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0
|
6726
|
March 18, 2018
|
|
(i) Hydrogen is not a metal but it has been assigned a place in the reactivity series of metals. Explain
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0
|
2758
|
March 18, 2018
|
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Write the names and symbols of two most reactive metals. Explain by drawing electronic structure how any one of them reacts with a halogen
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0
|
1829
|
March 18, 2018
|
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Two ores A and B were taken. On heating ore A gives C02 whereas, ore B gives S02. What steps will you take to convert them into metals?
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0
|
928
|
March 18, 2018
|
|
What are ionic or electrovalent compounds? Give an example of ionic compound. Explain with reason four properties of these compounds
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0
|
3138
|
March 18, 2018
|
|
State reason for the following: Lemon is used for restoring the shine of tarnished copper vessels
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0
|
3919
|
March 18, 2018
|
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Explain how the properties of an alloy are different from those of constituent metals
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0
|
3838
|
March 18, 2018
|
|
In the formation of the compound XY, atoms of X lost one electron each while atoms of Y gained one electron each. What is the nature of bond in XY?
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0
|
3307
|
March 18, 2018
|
|
Which two metals do not corrode easily?
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0
|
1862
|
March 18, 2018
|
|
A metal M is found in nature as MC03. It is used in galvanising iron articles
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|
0
|
5805
|
March 18, 2018
|
|
How can a layer of aluminium oxide on an aluminium object be made thicker?
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0
|
2455
|
March 18, 2018
|
|
A metal that exists as a liquid at room temperature is obtained by heating its sulphide in the presence of air. Identify the metal and its ore and give the reaction involved
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0
|
5550
|
March 18, 2018
|
|
Which material will be used as anode and cathode for refining of silver metal by this process?
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|
0
|
3143
|
March 18, 2018
|
|
An ore on heating in air produces sulphur dioxide. Which process would you suggest for its concentration?
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|
0
|
6192
|
March 18, 2018
|
|
What is meant by refining of metals? Describe the electrolytic refining of copper with a neat labelled diagram
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|
0
|
22279
|
March 18, 2018
|
|
Give the differences between electrolytic reduction and reduction with carbon
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|
0
|
6029
|
March 18, 2018
|
|
Give reasons: Platinum, gold and silver are used to make jewellery
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0
|
19262
|
March 18, 2018
|
|
Iqbal treated a lustrous, divalent element M with sodium hydroxide
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|
0
|
5399
|
March 18, 2018
|
|
An element A bums with golden flame in air. It reacts with another element B
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|
0
|
871
|
March 18, 2018
|