ANSWER IN ONE SENTENCE

1. Name a metal used for wrapping chocolates and food stuff.

Ans. Aluminium is used for wrapping chocolates and food stuff.

2. Which chemical process is used for obtaining a metal from its oxide?

Ans. A chemical process reduction is used fro obtaining a metal from its oxide.

3. From which ore is aluminium extracted?

Ans. Aluminium is extracted from bauxite (Al₂O₃. 2H₂O)

4. Name the reducing agent which reduces the iron ore in the blast furnace.

Ans. Carbon monoxide reduces the iron ore in the blast furnace.

5. Name the nonmetal used as an electrode in an electrolytic cell.

Ans. Carbon, in the form of graphite is used as an electrode in an electrolytic cell.

6. Name the allotropes of sulphur.

Ans. Rhombic sulphur and monoclinic sulphur are allotropes of sulphur.

7. What does ammonia fountain experiment demonstrate?

Ans. Ammonia fountain experiment demonstrate the following

1. Ammonia gas is highly soluble in water.
2. It is basic in nature.

8. Name the main alloy of iron.

Ans. Steel is the main alloy of iron.

9. Name the main alloy of Aluminium.

Ans. Duralumin is the main alloy of Aluminium.

10. Name the most stable allotrope of sulphur at ordinary temperature.

Ans. Rhombic sulphur is the most stable allotrope of sulphur at ordinary temperature.

11. State the shapes of (i) Rhombic sulphur (ii) Monoclinic sulphur.

Ans. Rhombic sulphur is octahedral shaped. Monoclinic sulphur is needle shaped.

12. State the position of sulphur in the periodic table.

Ans. Sulphur belongs to the VIA group i.e. group 16 and the 3^rd period of the periodic table.

13. What is the sublimate of sulphur called?

Ans. The sublimate of sulphur is called flower of sulphur.

14. What is milk of sulphur?

Ans. Sulphur obtained by chemical reaction as precipitate is called milk of sulphur.

15. What are the components of gun powder?

Ans. Gun powder contains sulphur, charcoal and potassium nitrate.

16. Which two allotropes of sulphur are soluble in carbon disulphide?

Ans. Rhombic sulphur and monoclinic sulphur are two allotropes of sulphur which are soluble in carbon disulphide.

17. State the use of dry ice.

Ans. Dry ice is used as a coolant in storage.

18. Give one test to detect the presence of carbon dioxide.

Ans. Fresh lime water turns milky in the presence of carbon dioxide.

19. Name the method of collection of hydrogen sulphide gas.

Ans. Hydrogen sulphide gas is collected in a gas jar by the upward displacement of air.

20. Name the ores of iron.

Ans. Haematite (Fe₂O₃), Magnetite (Fe₃O₄), limonite (2Fe₂O₃.3H₂O) and siderite (FeCO₃) are the main ores of iron.

21. How is alloy prepared?

Ans. An alloy is prepared by melting the main metal, and then dissolving the other element in it in a specific proportion.

22. State the uses of steel?

Ans. Steels are used in Construction of ships, vehicles, bridges etc.

23. State the uses of stainless steel.

Ans. Stainless steel is used in Utensils, cutlery, automobile parts, surgical instruments etc.

24. State the uses of Tungsten steel.

Ans. Tungsten steel is used in High speed cutting tools.

25. State the uses of Manganese steel.

Ans. Manganese steel is used in rock drills.

26. State the uses of duralumin.

Ans. Duralumin is used in parts of sir of air crafts and buses, cooker, etc.

27. Name two alloys of iron.

Ans The alloys of iron are steel, stainless steel, tungsten steel etc.

28. Where does CO₂ occur in nature?

Ans. Carbon dioxide occurs in atmospheric air, caves and some minerals springs.

29. How does carbon dioxide released in the atmosphere?

Ans. Carbon dioxide is released in the atmosphere through burning of fuel, natural gases, respiration and fermentation.

30. How does carbon dioxide gas is collected?

Ans. Carbon dioxide gas is collected in a gas jar by the upward displacement of air.

31. Name the main ores of aluminium.

Ans. Bauxite (Al₂O₃.2H₂O) and Cryolite (AlF₃.3NaF) are the main ores of aluminium. 

Metallurgy

Ans. The process of extraction of metals from their ores, refining, and alloying them is called metallurgy. The three important steps involved in the extraction of metals from their ores are:

1. Preliminary treatment: - In the preliminary treatment, the gangue is removed to concentrate the ore.
2. Chemical reduction: - The reduction can be brought about in two ways:
1. The reducing agent reduces the metal oxide to metal.
2. The reduction by electrolysis.
3. Refining: - The metal obtained by chemical reduction contains impurities. The impure metal is purified. 

Ore (Text Book)

Ans.

1. The mineral from which a metal can be extracted profitably is called an ore.
2. When an ore is mined from the earth, it always contains impure sand and rocky material.
3. The impurity of sand and rocky material present in an ore is called cangue.
4. The gangue is mainly composed of silica.
5. Main ores of iron: Haematite (Fe₂O₃), Magnetite (Fe₃O₄).
6. Main ores of aluminium Bauxite (Al₂O₃. 2H₂O)

Mineral (Text Book)

Ans.

1. A mineral is a material in the earth’s crust in which elements and compounds of inorganic nature are formed naturally.
2. Many minerals find applications in human life, and therefore are mined from the earth’s crust.
3. They are not evenly distributed over the world. The concentrated deposits of certain minerals containing a particular element are found in some places. These deposits are called ore of that element. 

OXIDES OF METALS AND NON METALS

Distinguish between metals and nonmetals with respect to the following points.

Physical state, Lustre, Density, Ductility and malleability Brittleness, conduction of heat and electricity, Electronic configuration, Formation of ions, Reaction with dilute acids, Nature of oxides, Reactivity.

Metals

Nonmetals

1.     Physical state: - Under ordinary conditions of pressure and temperature, metals are generally solid, except mercury and gallium which are liquids. 2.     Lustre: - Metals usually have a high lustre called metallic lustre. 3.     Density: - Metals usually have high density, except sodium and potassium. 4.     Ductility and malleability: - Metals are ductile and malleable. 5.       Brittleness: - Metals are usually hard, but not brittle, except sodium, potassium, zinc and lead. 6.     Conduction of heat and electricity: - Metals are good conductors of heat and electricity. 7.     Electronic Configuration: - The atoms of metals usually have less than four electrons in their outermost orbits. 8.     Formation of ions: - The property of metals to form positive ions (cations) by losing valence electrons is called electropositive character. 9.     Reaction with dilute acids: - Most of the metals react with mineral acids forming the corresponding salts. 10.  Nature of oxides: - Both metals and nonmetals combine with oxygen to form oxides. Mostly metals form basic oxides. These oxides react with acids to form salt and water. 11.  Reactivity: - If the number of electrons in the outermost orbit of the atom of a metal is less, then the metal is more reactive.

1.     Physical state: - Under ordinary temperature, nonmetals may be solid, liquid or gaseous. 2.     Lustre: - Nonmetals lack lustre, except carbon as diamond and iodine. 3.     Density: -Nonmetals have low density 4.     Ductility and Malleability: - Non metals are not ductile and malleable. 5.     Brittleness: - Nonmetals are brittle in the solid state. 6.     Conduction of heat and electricity: - Nonmetals are bad conductors of heat and electricity. 7.     Electronic configuration: - The atoms of nonmetals usually have more than four electrons in their outermost orbits. 8.     Formation of ions: - The property of non metals to form negative ions (anions) by gaining electrons is called electronegative character. 9.     Reaction with dilute acids: - Nonmetals generally do not react with dilute mineral acids. 10.  Nature of oxides: - Both metals and nonmetals combine with oxygen to form oxides. Mostly metals form basic oxides. These oxides react with acids to form salt and water. 11.  Reactivity: - If the number of electrons in the outermost orbit of the atom of a nonmetal is more, then the nonmetal is more reactive.

Hydrogen sulphide and Ammonia

Hydrogen Sulphide	Ammonia
Hydrogen sulphide has an offensive odour like that of rotten eggs. It is acidic in nature. It is collected by upward displacement of air. It turns moist blue litmus paper red.	Ammonia has a sharp, pungent and irritating odour. It is basic in nature. It is collected by the downward displacement of air. It turns moist red litmus paper blue.

Carbon dioxide and Ammonia.

Carbon dioxide	Ammonia
Carbon dioxide is odourless. it is collected by upward displacement of air. It turns moistened blue litmus red. It is fairly soluble in water	Ammonia has sharp, pungent and irritating odour. It is collected by the downward displacement of air. It turns moistened red litmus blue. It is highly soluble in water.

Rhombic Sulphur and Monoclinic Sulphur

Rhombic Sulphur	Monoclinic Sulphur
1.     The crystals of rhombic sulphur are rhombic. 2.     It is the most stable allotrope of sulphur at normal temperature. 3.     It is opaque. (non – transparent) 4.     It is converted into monoclinic sulphur when heated above 94.50C.	1.     The crystals of monoclinic sulphur are monoclinic or needle shaped. 2.     It is stable only above 94.50C 3.     It is Transparent. 4.     AT temperature lower than 94.50C, it is slowly converted into rhombic sulphur.

We can obtain a fountain of ammonia gas. (Text Book)

Ans. We can obtain a fountain of ammonia gas in the following manner.

1.     Ammonia gas is highly soluble in water. A test tube is filled with ammonia gas.

2.     A Jet Tube is fixed with test tube using a rubber cork.

3.     Red litmus solution is taken in the beaker.

4.     The test tube is fixed to a stand and the open end of the jet tube is inserted in the litmus solution.

5.     Red litmus solution is sucked in the test tube, since ammonia is a colourless basic gas and hence it turns red litmus solution blue, hence blue fountain is formed. 

Metals are good conductors, while nonmetals are poor conductors of Electricity.

Ans.

1. The electrons in the outermost orbit of the atoms of metals are free to move throughout the metal.
2. In the absence of potential difference, these electrons move in different direction and with different speed. There is no net flow of electrons in any direction.
3. When a potential difference is applied between the ends of metal wire, the net movement of the electrons from one end of the wire to the other end constitutes electric current.
4. But, nonmetals do not possess such free electrons. Hence, metals are good conductors, while nonmetals are poor conductors of electricity. 

We get a typical, strong odour at public urinals and cattle sheds.

Ans.

1. The urine of animals (including human beings) contains many nitrogenous compounds.
2. The bacterial decomposition of these nitrogenous compounds produces ammonia.
3. Ammonia has a strong, pungent and irritating odour.
4. Hence, we get a typical, strong odour at public urinals and cattle sheds. 

Carbon dioxide is used as a fire extinguisher.

Ans.

1. Carbon dioxide is not combustible and does not support combustion.
2. When it spread on a burning object, it covers the object and separates it from air. Without air (i.e. oxygen) the fire is extinguished.
3. It is heavier than air as well as non poisonous.
4. Hence, Carbon dioxide is used as a fire extinguisher.

When carbon dioxide is passed through lime water, it first turns milky and then turns colourless.

Ans.

1. When carbon dioxide is passed through lime water, initially white insoluble calcium carbonate is formed. Hence lime water turns milky.

When carbon dioxide is passed through lime water for a longer time, it reacts with calcium carbonate to form colourless, water soluble calcium bicarbonate. Hence, the lime water turns colourless.

A magnesium ribbon continues to burn brilliantly in a gas jar containing carbon dioxide.

Ans.

1. Magnesium is a strong reducing agent.
2. When a burning magnesium ribbon is introduced in a gas jar containing carbon dioxide, magnesium reduced carbon dioxide to carbon.
3. This reaction is exothermic.
4. Hence, a magnesium ribbon continues to burn brilliantly in the gas jar containing carbon dioxide. 

Silver ornaments should not be used in the laboratory.

Ans.

1. Inside the laboratory, there are traces of hydrogen sulphide in the atmosphere.
2. Hydrogen sulphide reacts with silver to form silver sulphide which is black in colour.
3. Thus, silver ornaments should not be used in the laboratory otherwise it becomes black. 

Acidified solution of potassium dichromate turns green when H2S is passed through it.

Acidified solution of potassium dichromate turns green when H₂S is passed through it.

Ans.

1. Hydrogen sulphide is a reducing agent.
2. When it is passed through an acidified solution of potassium dichromate, it reduces orange – coloured potassium dichromate to green – coloured chromium sulphide.
3. Hence, the solution turns green. 

Hydrogen sulphide is useful as a reagent in the laboratory to detect the metal (basic) cations.

Ans.

1. Hydrogen sulphide reacts with salts of a number of metals forming the corresponding metal sulphides.
2. These sulphides vary in colour, depending upon the metal present, and are insoluble in water.
3. From the colour of their precipitate, the metal cations can be conveniently detected.
4. Hence, Hydrogen sulphide is useful as a reagent in the laboratory to detect the metal cations. 

When H2S gas is passed through an acidified solution of CuSO4, a black precipitate is obtained.

Ans.

1. Hydrogen sulphide reacts with an acidified solution of CuSO_4­, to form a black insoluble copper sulphide.
2. Hence, when H₂S gas is passed through an acidified solution of CuSO₄, a black precipitate is obtained. 

Aluminium oxide is classified as an amphoteric oxide. (Textual Book)

Ans.

1. Aluminium oxide have acidic as well as basic functions and reacts with acids as well as alkalies to form salt and water.
2. An oxide which can have acidic as well as basic functions is called an amphoteric oxide. They react with acids as well as bases to form salt and water.
3. Hence, Aluminium oxide (Al₂O₃) is classified as an amphoteric oxide. 

Limestone is mixed with iron ore for extraction of iron in blast furnace. (Text Book)

Ans.

1. In the blast furnace, limestone decomposes to calcium oxide.
2. Calcium oxide combines with silica present in Iron ore to form a slag of calcium silicate.
3. This slag can be easily removed from the bottom of the blast furnace.
4. Hence, limestone is mixed with iron ore for extraction of iron in blast furnace. 

Metals have electropositive character.

Ans.

1. The atoms of metals have less than four electrons in their outermost orbits.
2. They can form positive ions by losing these electrons.

The property of metals to form positive ions by losing electrons is called its electropositive characters. 

Sulphur deposits on the earth’s surface are found as rhombic sulphur. (Text Book)

Ans. Sulphur has catenating power. It has two crystalline allotropes

a.      Monoclinic and

b.     Rhombic

1. Monoclinic sulphur is stable between 94.5⁰C and 120⁰C. This temperature is much higher than the average temperature of the earth’s surface.
2. Rhombic sulphur is stable at the temperature below 94.5⁰C. Over a period when monoclinic sulphur is cooled, it is get converted into rhombic sulphur.

Hence, sulphur deposits on the earth’s surface are found as rhombic sulphur. 

Define

1.     Allotropy: - The property by which an element exists in tow or more crystalline forms is called allotropy.

2.     Alloy: - An alloy is a homogeneous mixture of two or more metals or metal and a nonmetal.

3.     Calcinations: - The process of strongly heating the concentrated ore in the limited supply of air and converting into its oxide is called calcinations.

4.     Dry ice: - Solid carbon dioxide is called dry ice.

5.     Ductility: - The property of a metal due to which it can be drawn into a wire is called ductility.

6.     Gangue: - The unwanted material present in an ore is called gangue. For example impure sand and rocky material in an ore.

7.     Malleability: - The property of a metal due to which it can be hammered into a thin sheet without cracking is called malleability.

8.     Metal: - The element which can form positive ions by the loss of electrons is called metal. Iron and copper are metals.

9.     Metallurgy: - The process of extraction of metals from their ores, refining, and alloying them is called metallurgy.

10.  Metalloid: - The element which shows the properties of metals as well as those of nonmetals is called a metalloid. Arsenic and antimony are metalloids.

11.  Milk of sulphur: - Sulphur obtained by chemical reaction as precipitate is called milk of sulphur.

12.  Mineral: - A mineral is a material in the earth’s crust in which elements and compounds of inorganic nature are formed naturally.

13.  Nonmetal: - The element which can form negative ions by the gain of electrons is called nonmetal. Phosphorus and sulphur are nonmetals.

14.  Ore: - The mineral from which a metal can be extracted profitably is called an ore.

15.  Pig iron: - The iron which is obtained from the blast furnace is called cast or pig iron. It contains carbon as major impurity upto 4%.

16.  Reduction: - The chemical reaction in which oxygen is removed from a compound is called reduction. Or the conversion of metal ion into elemental metal is called reduction. Or the process of obtaining a metal from its oxides is called reduction.

17.  Refining: - The process of purification of an impure metal is known as refining of the metal.

18.  Roasting: - The process of heating the concentrated ore to a high temperature in excess of air, and converting into its oxide is called roasting. 

Road Transport V/s Rail Transport

Sr. No.	Basis of Difference	Road Transport	Rail Transport
1.	Speed	Road transport has limited speed due to bad road conditions, accidents, etc.	It has considerable speed since it runs on tracks which rarely get disturbed.
2.	carrying capacity	It has limited carrying capacity.	It has huge carrying capacity.
3.	Cost of construction and maint’ce`	It requires limited capital investment in terms of construction of road, vehicles and their maintenance.	The cost of construction of trains, railway tracks is high. Also the maintenance of trains, tracks and stations is high.
4.	Distance	Recommended for short distance.	Recommended for both short and long distance.
5.	Transport charges	Transport charges are not fixed but are high due to increased fuel prices.	Transport charges are relatively low and are fixed according to the distance.
6.	Door to door service	It provides door to door service.	It does not provide door to door service.
7.	Means of transport	It uses animal’s carts, motor-cycles three and four wheelers.	It uses passenger and goods train.
8.	Ownership	Ownership is in the hands of private parties.	Ownership is in the hands of the government.
9.	Safety	It provides limited safety to goods from sun, rain, wind, etc.	Goods are kept in locked wagons which provides protection against sun, wind, rain etc.