"AKC SCIENCE CLASSES"
CLASS 10 TH (CBSE AND MP BOARD)
CHAPTER 03
METALS AND NON-METALS
INTEXT QUESTIONS AND ANSWER
NCERT INTEXT QUESTIONS (PAGE NO. 40)
Q.01:- Give an example of a metal which
(ⅰ) is a liquid at room temperature.
(ⅱ) can be easily at room temperature.
(ⅲ) can be easily cut with the knife.
(ⅳ) is a poor conductor of heat.
Ans:- (ⅰ) Mercury
(ⅱ) Sodium
(ⅲ) Silver
(ⅳ) Lead.
Q.02:- Explain the meanings of malleable and ductile.
Ans:- Malleable is the property by which metals can be beaten into sheets with hammering without returning to previous condition.
Ductile is the ability of metals to be drawn in thin wires.
NCERT INTEXT QUESTIONS (PAGE NO. 46)
Q.01:- Why is sodium kept immersed in kerosene oil?
Ans:- Sodium is very reactive. If kept exposed to air, it catches fire.
Q.02:- Write equations for the reactions of
(ⅰ) iron with steam.
(ⅱ) Calcium and potassium with water.
Ans:-
(ⅰ) 3Fe + 4H2O(g) → Fe3O4 + 4H2
Iron Magnetic
oxide
(ⅱ) Ca + 2H2O → Ca(OH)2 + H2
Calcium Calcium
hydroxide
2K + 2H20 → 2KOH + H2
Potassium (Cold) Potassium
hydroxide
Q.03:- Samples of four metals A,B,C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows:-
(ⅰ) Which is the most reactive metals?
(ⅱ) What would you observe if B is added to a solutions of Copper(Ⅱ) sulphate?
(ⅲ) Arrange the metals A,B,C and D in the order of decreasing reactivity.
Ans:-
(ⅰ) Most reactive metals B. From the table, B can displace iron and not Zn from their solutions. So, Zn is more reactive than B. But B is more reactive than iron. B is more reactive than A, C and D, since these are less reactive than iron.
(ⅱ) B is more reactive than iron which is more reactive than copper. Hence, B is more reactive than copper and will displace copper from its solution. The following reaction will take place when B is added to a solution of copper sulphate. The color of copper sulphate will fade away.
B + CuSO4 → Cu + BSO4.
(ⅲ) D is least reactive, C is less reactive than A since A is more reactive than copper but C is less reactive than copper.
∴ B > A > C > D.
Q.04:- Which gas is produced when dilute hydrochloric acid is added to a reactive metal ? Write the chemical reaction when iron reacts with dilute H2SO4.
Ans:- Hydrogen gas is produced when dilute hydrochloric acid is added to a reactive metals.
Iron and dilute H2SO4
Fe + H2SO4 → FeSO4 + H2
Q.05:- What would you observe when zinc is added to a solution of iron(Ⅱ) sulphate ? Write the chemical reaction that takes place.
Ans:- Zinc is more reactive than iron. So, when zinc is added to a solution of iron(Ⅱ) sulphate, iron is removed from solution and green color of iron sulphate fades away.
Zn(s) + FeSO4(aq) → Fe(s) + ZnSO4(aq).
NCERT INTEXT QUESTIONS (PAGE NO. 49)
Q.01:- (ⅰ) Write the electron-dot structures for sodium, oxygen and magnesium.
(ⅱ) Show the formation of Na2O and MgO by the transfer of electrons.
(ⅲ) What are the ions present in these compounds?
Ans:- (ⅰ).
(ⅲ) In Na2O, ions present are Na+ and O-2
In MgO, ions present are Mg+2 and O-2
Q.02:- Why do ionic compounds have high melting points?
Ans:- Ionic compounds do not exist as molecules but exist as aggregates of a large number of positive and negative ions due to strong electrostatic attractions. The number of ions in an aggregate depends on the relative size of positive and negative ions. Thus ionic compounds have high melting points because considerable energy is required to break these aggregates.
NCERT INTEXT QUESTIONS (PAGE NO. 53)
Q.01:- Define the following terms:-
(ⅰ) Mineral (ⅱ)Ore (ⅲ)Gangue
Ans:- (ⅰ) MINERALS :- The elements and compounds which occur naturally in the earth's crust are known as minerals.
(ⅱ) ORE :- The minerals which contain in a high percentage of the metal, i.e., the mineral from which a metal can be profitably extracted is called an ore.
(ⅲ) GANGUE :- Ores mined from the earth are usually contaminated with large amounts of impurities like sand, soil, mud etc. These are called gangue.
Q.02:- Name two metals which are found in nature in the free state.
Ans:- Gold and Platinum.
Q.03:- What chemical process is used for obtaining a metals from its oxide?
Ans:- Metal oxides can be converted to metal by a process called reduction. For example, Zinc oxide is reduced to metallic zinc by heating with carbon.
ZnO(s) + C(s) → Zn(s) + CO(g)
Besides carbon, highly reactive metals like sodium, calcium, highly reactive metals like sodium, calcium, aluminium etc., are used as reducing agents. These displace metals of low reactivity from their oxide, e.g.,
Fe2O3(s) + 2Al(s) → 2 Fe(l) + Al2O3(s) + Heat
NCERT INTEXT QUESTIONS (PAGE NO. 55)
Q.01:- Metallic oxides of zinc, magnesium and copper were heated with the following metals:-
In which cases will you find displacement reactions taking place?
Ans:-
Q.02:- Which metals do not corrode easily?
Ans:- Gold and Platinum.
Q.03:- What are alloys?
Ans:- An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. It is prepared by first melting the main metal, and then dissolving the required amount of other metals or non-metals. The mixture is then cooled to form an alloy of a given composition.
