(1) Which of the following non-metals is a liquid?
(d) Bromine Solution
Answer is D
(2) Which of the following methods is suitable for preventing an iron frying pan from rusting?
(a) Applying grease
(b) Applying paint
(c) Applying a coating of zinc
(d) All of the above. Solution
Answer is C
Long Answer type
(i) Reactivity of A1 decreases if it is dipped in HNO3
(ii) Carbon cannot reduce the oxides of Na or Mg.
(iii) NaCI is not a conductor of electricity in solid state whereas it does conduct electricity in aqueous solution as well as in molten state.
(iv) Metals like Na, K, Ca and Mg are never found in their free state in nature. Question 2
Metals replace hydrogen from dilute acids, whereas non-metals do not. Why? Answer
Non-metals do not displace hydrogen from dilute acids is because unlike metals, non-metals do not have a tendency to lose electrons but to gain electrons. Metals have a tendency to lose electrons. These electrons, which are readily lost by reactive metals like sodium, potassium etc are accepted by hydrogen ions of the acids, reducing them to hydrogen gas (H2).
What is meant by refining of metals? Describe the electrolytic refining of copper with a neat labeled diagram. Question 4 An ore on heating in air produces sulphur dioxide. Which process would you suggest for its concentration? Describe briefly any two steps involved in the conversion of this concentrated ore into related metal. Question 5
Why aluminum oxide is considered an amphoteric oxide? Answer
Aluminium oxide is called Amphoteric oxide because it has both acidic and basic properties.
Basic property :
Al2O3 + H+ ----> Al3+ + H2O
State the property utilize in the following:
(a) Graphite in making electrodes.
(b) Electrical wires are coated with polyvinyl chloride (PVC) or a rubber like material.
(c) Metal alloys are used for making bells and strings of musical instruments. Question 7
Explain with the help of an activity that metals conduct electricity. Draw a diagram for the same. Answer
We need Bulb,Battery, Metal Nail and wires
(1) Connect one of bulb with nail by wire
(2) connect second end of a bulb with the wire to the battery
(3) connect battery with the metal nail by wire
We will observed Bulb will glow.
And this proves Metals conduct electricity.
Name a metal which has very low melting point and a non-metal which has very high melting point. Answer
Caesium and gallium metals have low melting point. Diamond a allotrope of carbon has very high melting point which is a non metal
Write one example of each of the following:
(a) Most malleable metal and most ductile metal.
(b) The best conductor of heat and the poorest conductor of heat.
(c) A metal with highest melting point and a metal with lowest melting point. Question 10
(a) Which metal from the following can displace zinc from zinc sulphate solution?
Lead, copper, magnesium, silver
Write the equation of the chemical reaction involved.
(b) Arrange metals Ca, Al, Cu and Au in decreasing order of reactivity. Answer
agnesium will displace zinc from its sulphate
g(s) + ZnSO4(aq) ---> MgSO4(aq) +Zn(s)
Decreasing order of reactivity of metals:
Ca > Al > Zn > Cu > Ag > Au
(a) A substance X, an oxide of a metal, is used extensively in the cement industry. This element is found in our bones also. On treatment with water it forms a solution which turns red litmus blue. Identify X and also write the chemical reaction involved.
(b) Choose a metal from the following metals which reacts only with hot water:
Sodium, magnesium, iron
Mention the products formed during the reaction. Question 12
Food cans are coated with tin rather than zinc.
Give suitable reason for the following
(a)Shining surface of metals is tarnished after some time.
(b) Sodium and potassium are kept under kerosene oil.
(c) Generally no hydrogen gas is involved when metals react with dilute nitric acid
(d) Some alkali metals can be cut with a knife. Question 13 How metals can be differentiated from non – metals on the basis of any three chemical properties? Question 14
(a) Support your answer with chemical equations in each case. What happen when magnesium ribbon is burnt in air? What is the state of the metal oxide in the product formed?
(b) An element A forms two oxides AO and AO2.The oxide AO is neutral whereas the oxide AO2 is acidic in nature. Would you call element A a metal or non – metal? Question 15
(a) What are the bases which are soluble in water called?
(b) Write any four uses of bases. Question 16
When a copper wire is left in silver nitrate solution, it is observed that the solution turns bluish green.
(a) Explain the observation.
(b) Write the balanced chemical equation to represent the change taking place. Question 17
What happens when a piece of:
(a) Aluminium metal is added to dilute hydrochloric acid.
(b) Zinc metal is added to copper sulphate solution.
(c) Silver metal is added to copper sulphate solution.
Also write balanced chemical equation, if the reaction occurs. Answer
(a) Aluminium is more reactive than hydrogen and is placed above hydrogen in the reactivity series. Thus, when aluminium metal is added to dilute HCl, it displaces hydrogen from the acid and forms aluminium chloride and hydrogen gas. Following is the chemical equation for the reaction
2Al (s) + 6HCl (aq) -> 2AlCl3 (s) + 3H2 (g)
(b) Zn + CuSO4 -> ZnO4 + Cu
(c) Ag+ CuSO4 ->No reaction
Write balanced chemical equation for the reaction of:
(a) aluminium when heated in air. Write the name of product.
(b) iron with steam and name the products obtained.
(c) calcium with cold water. Why does calcium start floating in water? Answer
product Name is - aluminium oxide
(b) Fe + H2O ---- > Fe(OH)2
(c) Actually, when calcium reacts with water, the reaction is less vigorous and it forms calcium hydroxide with release of hydrogen gas, but the heat evolved is not sufficient for hydrogen gas to catch fire and so it sticks over the surface of calcium hydroxide and the wall of container which do not let the calcium hydroxide to sink and it continues to float on the water surface .
The reaction involved is :
Ca + 2H2O --> Ca(OH)2 + H2
Iron displaces copper from copper sulphate solution, zinc displaces iron from iron sulphate solution and copper displaces silver from silver nitrate solution. On the basis of these reactions arrange the four metals involved in order of their reactivity. Give balanced chemical equations in each case. Answer
The reactivity order is as follows:
The atomic number of magnesium is 12 and of chlorine is 17. Show the formation of magnesium chloride by the transfer of electrons. Question 21v
(a) Write the electron – dot structure for calcium and sulphur.
(b) Show the formation of CaS by the transfer of electrons.
(c) Name the ions present in this compound CaS.
(Atomic number of Ca = 20, S = 16) Question 22
Write balanced chemical equations for the following reactions:
(a) Calcium carbonate on reaction with hydrochloric acid gives calcium chloride, water and carbon dioxide.
(b) Nitrogen reacts with hydrogen under pressure to form ammonia.
(c) Carbon disulphide burns in air to give carbon dioxide and sulphur dioxide. Answer
(a) CaCO3 + 2HCl -> CaCl2 + CO2 + H2O
(b) N2 + 3H2 -> 2NH3
(c) CS2 + 3O2 -> 2SO2 + CO2
Write chemical equations for the following reactions:
(a) A piece of calcium metal is dropped in water.
(b) Steam is passed over red hot iron.
(c) Zinc sulphide is heated in air. Answer
Ca(s) + 2H2O(l) -> Ca(OH)2 (aq) + H2 (g)
3Fe(s) + 4H 2 O (g) -> Fe 3 O 4(s) + 4H 2 (g)
2ZnS(s) + 3O2 -> 2ZnO(s) + 2SO 2 (g)
Define the terms:
(iii) Gangue. Question 25
What is meant by concentration of an ore? Why is it necessary to concentrate an ore before processing? Name an ore of mercury and copper. Question 26
Differentiate between the following:
(a) Reaction of magnesium and calcium with water.
(b) Roasting and calcinations processes giving an example of each.
(c) Nature of metal and non – metal oxides with an example. Question 27
How can sodium be obtained from sodium chloride? Question 28
(i) Define the term ‘anode mud’. Name the electrode made of pure metal.
(ii) Give the reactions taking place at cathode and at anode during the electrolytic refining of copper. Question 29
(a) Ores of both zinc and mercury are sulphide ores. Explain the methods used to extract these metals from their ores.
(b) Can we store concentrated solution of sodium hydroxide in a zinc container? Explain. Question 30
If a strip of aluminium with clean surface is dipped into an aqueous solution of copper sulphate for some time, the surface of the strip becomes brown. State the reason for this. Write balanced chemical equation for the reaction. Question 31
Which metal is more reactive between copper and iron? How can you prove it? Question 32
Distinguish between the following:
(a) Electrolytic reduction and electrolytic refining.
(b) Mineral and ore.
(c) Alloys and amalgams. Answer
This method is used for refining less reactive metals such as copper and silver.
This method is used for extraction of reactive metals like sodium and potassium from their ores.
The aqueous solution of the salt is used as an electrolyte.
The molten salt of the metal is used as an electrolyte.
All the naturally occurring substances of metals which are present in the earth’s crust are known as Minerals.
Ores are usually used to extract metals economically. A large amount of metals are present.
All Minerals are not ores.
All ores are minerals.
Minerals are native form in which metals exist.
Ores are mineral deposits.
An alloy is a homogeneous metallic solution composed of two or more elements.One of the elements in the alloys is essentially a metal, while the other element or elements may be metals or non-metals like carbon, silicon, sulphur or boron
Alloys of mercury with other metals like sodium, potassium,gold and zinc...etc are called amalgam
Alloys are harder and tougher than the base metal and are resistant to corrosion.
Silver-tin amalgams are useful for the dental cavities.
Duralumin consists of Al: 95% Cu: 4% Mn: 0.5%
Name two metals which do not corrode easily. Give an example in each of the following case to support that:
(a) Corrosion of some metals is an advantage.
(b) Corrosion of a metal is a serious problem.
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