Frequently Tested Topics:
Important Past Questions:
Write the formula of cryolite.
Name: the process of heating an ore to a high temperature in the presence of air.
(2006, 2014, 2017, 2019)
Mention one reason for the use of aluminium in thermite welding.
(2004, 2009, 2014)
Pure aluminium oxide is dissolved in _______ to make a conducting solution.
Name a compound added to lower the fusion temp. of the electrolytic bath in the extraction of Al.
(2006, 2014, 2016)
Name a metal which is liquid at room temperature.
A strip of copper is placed in 4 different colourless salt solns. They are KNO3, AgNO3, Zn(NO3)2 and Ca(NO3)2. Which one of the solns. will finally turn blue?
In the extraction of aluminium:
i) Which soln. is used to react with bauxite as a first step in obtaining pure aluminium oxide? (2007, 2016)
ii) Aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide. Write the equation for this reaction. (2007, 2016, 2018)
iii) Name the element which serves as the anode & cathode. (2007, 2008
iv) Write the equation for the reaction at the cathode during the extraction of aluminium by electrolysis. (2007, 2013, 2016, 2018)
v) Why is it necessary for the anode to be renewed periodically? (2008, 2013, 2015, 2016)
vi) State the reason for addition of caustic alkali to bauxite ore during purification of bauxite. Give balanced chemical equation for the reaction. (2012, 2015)
vii) Identify the components of the electrolyte other than pure alumina and the role played by each. (2008, 2011, 2012, 2013, 2015, 2017, 2019)
viii) Explain why powdered coke is sprinkled over the electrolytic mixture. (2015, 2017, 2019)
ix) At which elecrode is aluminium formed. (2008)
Name a metal present in cryolite other than aluminium.
State the main components of the following alloys:
i) Brass (2005, 2008, 2010, 2013, 2014, 2018)
ii) Duralumin (2010, 2014, 2018)
iii) Bronze (2014, 2016)
iv) Stainless steel (2010)
Choose the amphoteric oxide:
i) A] Silver oxide B] Copper [II] oxide C] Aluminium oxide D] Calcium oxide (2009)
ii) A] Calcium oxide B] Barium oxide C] Zinc oxide D] Copper [II] oxide (2013)
iii) SO2, SiO2, Al2O3, MgO, CO, Na2O (2015)
The most common ore of iron is ________ [calamine/haematite]
Name the process used for the enrichment of the sulphide ore.
Name the most common ore of aluminium from which the metal is extracted. Write the chemical formula of the ore.
Name the ore of zinc containing its sulphide.
Select the property which is not true for metals
A] metals are good conductors of electricity B] metals are malleable and ductile C] non-polar covalent compounds are formed from metals D] metals have 1, 2 or 3 valence electrons
Choose from the list of substances: acetylene gas, aqua fortis, coke, brass, barium chloride, bronze, platinum. - the substance which is an alloy of zinc, copper and tin.
Differentiate between calcination and roasting.
Choose the correct answer:
i) an alkaline earth metal
A] potassium B] calcium C] lead D] copper (2012)
ii) the metallic oxide which cannot be reduced by normal reducing agents
A] magnesium oxide B] copper [II] oxide C] Zinc oxide D] iron [III] oxide (2012)
Name the property possessed by metals by which they can be beaten into sheets.
Select which is not an alloy of copper:
A] Brass B] Bronze C] Solder D] Duralumin
Give scientific reasons:
i) zinc oxide can be reduced to zinc by using carbon monoxide, but aluminium oxide cannot be reduced by a reducing agent. (2015)
ii) alkali metals are good reducing agents. (2018)
Complete the following by selecting the correct option from the bracket:
i) Metals are good _____ (oxidising agents/reducing agents) because they are electron ______ (acceptors/donors)
ii) The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction _______ (Fe/Mg/Pb/Al)
iii) The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt is _______ (Al/Na/Mg/K)
Identify the term for:
i) The method used to separate ore from gangue by preferential wetting. (2016)
ii) Crushing of the ore into a fine powder. (2017)
i) an alloy of lead and tin that is used in electrical circuits (2017)
ii) a metal oxide that can be reduced by hydrogen. (2017)
Match the properties and uses of alloys in list 1 with the appropriate answer from list 2.
List 1: 1. The alloy that contains Cu and Zn, and is used for decorative articles.
2. It is stronger than aluminium, light and is used in making light tools.
3. It is lustrous, hard, corrosion resistant and used in surgical instruments
4. Tin lowers the melting point of the alloy and is used for soldering purpose.
5. The alloy is hard, brittle, takes up polish and is used for making statues.
List 2: A] Duralumin B] Brass C] Bronze D] Stainless steel E] Solder
Using the information below about X and Y, complete the following questions: