|
Choose a metal out of the following which reacts with hot water but not with cold water : Sodium, Magnesium, Iron
|
|
1
|
2539
|
March 29, 2019
|
|
What is an alloy? Name the constituents of 22-carat gold. Why is 24-carat gold converted to 22-carat gold?
|
|
1
|
2563
|
March 29, 2019
|
|
Why does magnesium powder reacts much more rapidly than magnesium ribbon with dilute sulphuric acid?
|
|
1
|
1999
|
March 29, 2019
|
|
Name any two non-metals which are used in industry. How is each one of them important to us
|
|
1
|
1525
|
March 29, 2019
|
|
A solution of copper sulphate was kept in an iron pot. After a few days, the iron pot
|
|
1
|
8909
|
March 29, 2019
|
|
What is the valency of silicon with a atomic number 14?
|
|
1
|
1949
|
March 29, 2019
|
|
What is seen to happen when a piece of sodium metal is dropped into water?
|
|
1
|
573
|
March 29, 2019
|
|
Why do metals not evolve hydrogen gas with nitric acid?
|
|
1
|
2799
|
December 27, 2018
|
|
How do you classify elements into metals and non-metals on the basis of their electronic configuration?
|
|
0
|
17955
|
March 18, 2018
|
|
Distinguish between ‘roasting’ and ‘calcination’. Which of these two is used for sulphide ores and why?
|
|
0
|
6465
|
March 18, 2018
|
|
Distinguish between ionic and covalent compounds under the following properties
|
|
0
|
10072
|
March 18, 2018
|
|
What is an ionic bond?
|
|
0
|
7076
|
March 18, 2018
|
|
(i) Hydrogen is not a metal but it has been assigned a place in the reactivity series of metals. Explain
|
|
0
|
2947
|
March 18, 2018
|
|
Write the names and symbols of two most reactive metals. Explain by drawing electronic structure how any one of them reacts with a halogen
|
|
0
|
1904
|
March 18, 2018
|
|
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?
|
|
0
|
1036
|
March 18, 2018
|
|
What are ionic or electrovalent compounds? Give an example of ionic compound. Explain with reason four properties of these compounds
|
|
0
|
3325
|
March 18, 2018
|
|
State reason for the following: Lemon is used for restoring the shine of tarnished copper vessels
|
|
0
|
4166
|
March 18, 2018
|
|
Explain how the properties of an alloy are different from those of constituent metals
|
|
0
|
3913
|
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?
|
|
0
|
3469
|
March 18, 2018
|
|
Which two metals do not corrode easily?
|
|
0
|
1971
|
March 18, 2018
|
|
A metal M is found in nature as MC03. It is used in galvanising iron articles
|
|
0
|
7635
|
March 18, 2018
|
|
How can a layer of aluminium oxide on an aluminium object be made thicker?
|
|
0
|
2649
|
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
|
|
0
|
5655
|
March 18, 2018
|
|
Which material will be used as anode and cathode for refining of silver metal by this process?
|
|
0
|
3322
|
March 18, 2018
|
|
An ore on heating in air produces sulphur dioxide. Which process would you suggest for its concentration?
|
|
0
|
6703
|
March 18, 2018
|
|
What is meant by refining of metals? Describe the electrolytic refining of copper with a neat labelled diagram
|
|
0
|
23489
|
March 18, 2018
|
|
Give the differences between electrolytic reduction and reduction with carbon
|
|
0
|
6427
|
March 18, 2018
|
|
Give reasons: Platinum, gold and silver are used to make jewellery
|
|
0
|
19474
|
March 18, 2018
|
|
Iqbal treated a lustrous, divalent element M with sodium hydroxide
|
|
0
|
5512
|
March 18, 2018
|
|
An element A bums with golden flame in air. It reacts with another element B
|
|
0
|
938
|
March 18, 2018
|