Metallurgy class 10 notes - ICSE CHEMISTRY

Metallurgy Important points for Final exam ICSE BOARD

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Notes of Metallurgy Chemistry ICSE

Mineral: Naturally occurring compounds of metals along with the earthly impurities.

Ore: The mineral from which metals are extracted easily and profitably.

Metallurgy: The process in which metals are extracted from their minerals.

Matrix (or) Gangue: The impurities that associated with an ore.

 

Metallurgy involves the following steps:

Step -I - Concentration of Ore-Removal of impurities.

Step - II - Conversion of ore to metal oxide.

Step - III - Reduction of the metal oxide to the metal.

Step - IV - Refining impure metal to pure metal.

 

 

Extraction of Aluminium from Bauxite ore:

Ore : Bauxite – Al₂O₃.2H₂O – Hydrated Aluminium oxide

 

Step I: Concentration of ore

            The matrix is removed by chemical method.

            Chemical used : Conc. Sodium hydroxide solution

            Process name: Baeyer’s process

 

æ      Al₂O₃.2H₂O + 2NaOH --> 2NaAlO₂ + 3H₂O

The amphoteric nature of Aluminium oxides makes it react with NaOH where as other impurities like Fe₂O₃ and SiO₂ do not react and will be separated out.

           

æ      NaAlO₂ + 2H₂O -->  NaOH + Al(OH)₃

Al(OH)₃ crystals are added to the dil. NaAlO₂ solution to further precipitate out Al(OH)₃ crystals this process is called seeding.

 

æ      2Al(OH)₃  --> Al₂O₃ + 3H₂O

                                                      Alumina

Step II : This step is not necessary as the pure ore is an oxide.

 

Step III : Reduction of pure Alumina to Aluminium.

            Aluminium oxide (Alumina) is not reduced by reducing agents because it is highly stable hence Alumina is reduced by electrolysis in Hall Heroult’s process.

 

Hall Heroult’s process

 

Electrolyte                   : Fused mixture of Alumina (Al₂O₃) , Cryolite (Na₃AlF₆) and

                                    Fluorspar (CaF₂) in the ratio 1:3:1.

Reason: Cryolite lowers the fusion point of Alumina (2050⁰C to 950⁰C)and enhances the conductivity of the electrolyte.

Electrolytic cell           : Steel tank with Carbon lining acts as cathode.

Electrodes                   : Anode – A series of Graphite electrodes

                                    Cathode – The electrolytic cell with Carbon lining

Graphite rods connected in a series is taken as anode instead of one Graphite rod because the Oxygen released at anode will oxidize them to CO and CO₂.

Precaution:

Coke powder is sprinkled on the surface of fused electrolyte.

Reason: It prevents the oxidation of anode by the atmospheric Oxygen and heat loss by radiation.

 

Electrolytic reaction involves the following steps:

Na₃AlF₆ --> 3Na⁺ + Al³⁺ + 6F ^–

CaF₂ --> Ca²⁺ + 2F ^–

Al₂O₃ --> 2Al³⁺ + 3O^{2 –}

at cathode : 2Al³⁺ + 6e ^–  --> 2Al                  product: pure Aluminium metal

at anode : 6O^{2 –} - 12e ^–  -->  3O₂                           product: Oxygen gas (CO and CO₂)

 

Step IV is not necessary because the Aluminium metal obtained in Hall Heroult’s process is 99.5% pure. (Further purification can be done by Hoope’s process.)

Class 10 Metallurgy notes ICSE CHEMISTRY

Metallurgy Notes - Important points for Board exam

Metal: Metal is an element which ionizes by losing one or more electrons.

ü  Metals have 1,2 or 3 electrons in their valence shell.

ü  They lose electrons and form positive ions (cations) hence they form electrovalent compounds.

Na – e^- --> Na⁺

Mg – 2e^- --> Mg²⁺

Al – 3e^- --> Al³⁺

 

Comparison between metals and non-metals:

Physical properties:

Metals	Non-metals
1.      Exist in solid state at room temp. Except: Mercury is liquid, Gallium melts at room temp.	1.      Exist as soft solids and gases. Except: Bromine is liquid at room temp.
2.      Have luster	2.      Do not have luster. Except: Iodine crystals, Diamond and Graphite shine
3.      Have high boiling and melting points. Except: Na, K, Hg etc	3.      Have low boiling and melting points. Except: Carbon, Silicon.
4.      High density. Except Na, K, Ca	4.      Low density except Diamond.
5.      Are malleable and ductile except zinc and Mercury	5.      Non-Malleable and non-ductile except Carbon fibre.
6.      Non- brittle but Zinc is brittle.	6.      Non-metals are brittle.
7.      Good conductors of electricity except Tungsten.	7.      Non-conductors except Graphite and gas Carbon.

 

Chemical properties- Comparison between Metals and Nonmetals:

Metals	Non-metals
1.      Have 1, 2 or 3 valence electrons.	1.      Have 4, 5, 6 or 7 valence electrons.
2.      They form cations by losing electron/s. And Reducing agents (donate electrons)	2.      Form anions by gaining electron/s. And Oxidizing agents (accept electrons).
3.      Electropositive elements.	3.      Electronegative elements.
4.      During electrolysis cations gain electrons (get reduced) and are discharged.	4.      Anions lose electrons (get oxidized) and are discharged.
5.      Active metals react with dil. acids to liberate Hydrogen gas. Reason: active metal can transfer electrons to the Hydrogen ions of acids and neutralize them to atoms.	5.      Non-metals do not give Hydrogen gas with dil. acids. Reason: Electron transfer does not take place from the non-metals to the Hydrogen ion of the acid.
6.      Metal oxides are basic in nature. (Al2O3, ZnO and PbO are amphoteric in nature).	6.      Non-metallic oxides are acidic in nature and form acids when dissolved in water. (CO, NO,N2O, H2O are neutral oxides)
7.      Metal chlorides are solids and non-volatile. Electrovalent compounds.	7.      Non-metallic chlorides are volatile liquids. Covalent compounds

Metallurgy Test

Electrolysis Test

Chemical Bonding - test

The Periodic Table

Practical Chemistry Test - anions

Practical Chemistry Test - Cations

Practical Chemistry Test - Observation Based

Sureshot questions in ICSE CHEMISTRY

Observation based questions - Practical chemistry 2

Questions on Analytical chemistry 

Identification of cations using Ammonium hydroxide and Sodium hydroxide

Identify the cation present in each of the following cases based on the colour of the precipitate formed.

1. A salt solution gives a gelatinous white precipitate with small amount of Ammonium hydroxide, and the precipitate is soluble in excess Ammonium hydroxide.

Ans: Zinc ion

2. A salt solution forms a reddish brown precipitate with Ammonium hydroxide which remains insoluble.

Ans:  Ferric ion

3. This salt solution gives a pale blue precipitate with Ammonium hydroxide, this precipitate turns deep (inky) blue solution in excess Ammonium hydroxide.

Ans: Cupric ion

4. When Ammonium hydroxide is added to this salt solution a dirty green precipitate is formed whih is isoluble in excess Ammonium hydroxide.

Ans: Ferrous ion

5. When this salt solution is treated with Ammonium hydroxide solution a white precipitate is formed and insoluble in excess Ammonium hydroxide.

Ans: Lead ion

6. A salt solution is treated with Sodium hydroxide then it gives a gelatinous white precipitate and that white precipitate disappears when excess Sodium hydroxide is added.

Ans: Zinc ion

7. When Sodium hydroxide solution is added to a salt solution, a pale blue precipitate is formed which remains insoluble in excess Sodium hydroxide.

Ans: Zinc ion

8. Two salt solutions A and B are treated with Sodium hydroxide and A reddish brown precipitate and a dirty green precipitate are formed respectively.

Ans: Solution 'A' contains Ferric ion

Solution 'B' contains Ferrous ion

Observation based questions - Practical chemistry - ICSE

Observation based questions - Practical chemistry - ICSE - IMPORTANT for VIVA

IDENTIFICATION OF GASES

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Click here to attempt sample test(MCQs) - Free

1. Name a gas which is neutral in nature and burns with blue flame.

Ans: Hydrogen gas

2. Name the gas which turns lime water milky but has no effect of acidified Potassium permanganate and acidified Potassium dichromate.

Ans: Carbon dioxide gas

3. The gas, which is greenish yellow in colour, turns moist blue litnus paper to red and then bleaches it.

Ans: Chlorine gas.

4. A which is released by the oxidation of Conc. HCl using an oxidizing agent.

Ans: Chlorine gas

5. A basic gas which is used in the manufacturing of a fertilizer called Urea.

Ans: Ammonia gas

6. These vapours turn anhydrous Copper sulphate to blue.

Ans: Water vapour

7. A suffocating gas which turns lime water milky and highly soluble in water.

Ans: Sulphur dioxide gas.

8. This gas is released when  Sodium chloride (mineral) is heated with a non-volatile acid.

Ans: Hydrogen chloride gas

9. A coloured gas which gives Iodine vapours with Potassium iodide crystals.

Ans: Nitrogen dioxide

10. A gas which is released when a dilute acid reacts with a metal sulphide.

Ans: Hydrogen sulphide

ICSE CHEMISTRY class 10 CHEMICAL BONDING - 4

ICSE CHEMISTRY CLASS 10 CHEMICAL BONDING - 4

Give reasons

1.      Electrovalent compounds are soluble in water but not in organic solvents.

2.      Electrovalent compounds undergo high speed reactions where as covalent compounds undergo slow reactions.

3.      CCl₄ does not conduct electricity.

4.      Covalent compounds exist as liquids, gases or soft solids.

Choose the correct answer.

1.      Which of the following does not favour formation of ionic bond:

A)    Lower I.P value of metallic atom

B)    Higher E.A value of non-metallic atom

C)    Lower E.A value of non-metallic atom

D)    Larger electronegativity difference between the combining atoms

2.      A compound ‘X’ consists of molecules only then the nature of the bonding in ‘X’ is:

3.      Which of the following is not a property of electrovalent compounds:

A)    High B.P and M.P

B)    Non conductors of electricity in their fused state

C)    Non volatile

D)    Crystalline solids

4.      The compound which is composed of three types of bonding:

5.      Metal loses electron/s to form cation/s. It is called ________

6.      Which one among the following is a polar covalent molecule?

A)    Water

B)    Methane

C)    CCl₄

D)    Chlorine

7.      Which of the following is not an electrovalent compound?

A)    NaCl

B)    MgO

C)    CCl₄

D)    CaCl₂

8.      Methane is a/an _____________ compound.

9.      Which of the following involves coordinate covalent bonding?

A)    Ammonia

B)    Calcium oxide

C)    Ammonium chloride

D)    Water

10.  Which of the following can be electrolyzed ?

A) H₂O         B) NaCl sol.    C) Solid MgCl₂           D) CCl₄

ICSE CHEMISTRY Class 10 ORGANIC CHEMISTRY - 5

ICSE CHEMISTRY ORGANIC CHEMISTRY - 5

ORGANIC CHEMISTRY IMPORTANT QUESTIONS

Distinguish between the following pair of compounds:

1.      Ethane and Ethene

2.      Ethene and Ethyne

3.      Ethanoic acid and Ethane

Match the following.

1.      Esters

2.      Ethene

3.      Ethyne

4.      Ethyl chloride is boiled with alc.KOH

5.      Ethyl chloride is boiled with aq.KOH

6.      Neutral FeCl₃

7.      Hydrolysis of Ethyl acetate

8.      Methylated spirit

9.      Lab preparation of Ethyne

10.  Acetylene linkage

11.  Elimination of Carbon dioxide

12.  Decolourizes Bromine water

A.    Ethene

B.     Fruity smell

C.     Gives are a precipitate with Ammoniacal CuCl

D.    Ethyne

E.     Ethyl alcohol

F.      –CºC–

G.    Decarboxylation

H.    Ethyl alcohol containing Methyl  alcohol

I.       Ethyl alcohol + acetic acid

J.       CaC₂ + cold H₂O