HELLO GUYS!
How are you all
So Today in This post I'm going to give you Periodic classification of elements For class 10th ,11th,12th
.
Believe me if you solve this fully then you can clear your exam very well.
metals and non metals Extra questions class 10
1. Which of the following is purest form of carbon?
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(a) Diamond
(b) Graphite
(c) Fullerene
(d) Charcoal
ANS: (c)
2. An element ‘X’ is yellow coloured solid, insoluble in water but soluble in carbon disulphide. It has low melting point 114.5°C. It boils at 445°C and it burns with pale blue flame forming pungent smelling gas ‘Y’ which turns moist blue litmus red and finally 1
colourless. ‘X’ and ‘Y’ are
(a) C, CO2 (b) N, NO2
(c) S, SO2 (d) I2, I2O5
ANS: (c)
3 Which of the following oxide(s) of iron would be obtained on prolonged reaction of iron with steam? 1
(a) FeO (b) Fe2O3
(c) Fe3O4 (d) Fe2O3 and Fe3O4
ANS: (c)
4 Generally metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on 1
reacting with metals (except Mn and Mg)?
(a) H2SO4 (b) HCl (c) HNO3 (d) All of these
ANS: (c)
5 Which of the following are not ionic compounds?
(i) KCl (ii) HCl (iii) CCl4 (iv) NaCl
(a) (i) and (ii) (b) (ii) and (iii)
(c) (iii) and (iv) (d) (i) and (iii)
ANS: (b)
6 Which one of the following four metals would be displaced from the solution of its salts by other three metals ? 1
(a) Mg (b) Ag
(c) Zn (d) Cu
ANS: (b)
7 An element A is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following
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(a) Mg (b) Na
(c) P (d) Ca
ANS: (b)
8 Reaction between X and Y, forms compound Z. X loses electron and Y gains electron. Which of the following properties is not shown by Z ?
(a) Has high melting point
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(b) Has low melting point
(c) Conducts electricity in molten state
(d) Occurs as solid
ANS: (b)
9 The electronic configurations of three elements X, Y and Z are X —2, 8; Y — 2, 8, 7 and Z — 2, 8, 2. Which of the following is 1
correct?
(a) X is a metal
(b) Y is a metal
(c) Z is a non-metal
(d) Y is a non-metal and Z is a metal
ANS: (d)
10 Although metals form basic oxides, which of the following metals form an amphoteric oxide?
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(a) Na (b) Ca
(c) Al (d) Cu
ANS: (c)
11 In the following questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion. 1
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion. (c) Assertion is true but the Reason is false.
(d) The statement of the Assertion is false but the Reason is true. Assertion: Al2O3 is an amphoteric oxide. Reason: Al2O3 reacts with acid as well as base to form salt and water.
ANS: (a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
12 In the following questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion. 1
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion. (c) Assertion is true but the Reason is false.
(d) The statement of the Assertion is false but the Reason is true. Assertion: Nitrogen is a non-metal. Reason: Nitrogen has 5 valence electrons.
ANS: (b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.
13 In the following questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the 1
correct alternative from the following:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion. (b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion. (c) Assertion is true but the Reason is false.
(d) The statement of the Assertion is false but the Reason is true. Assertion: Copper does not reacts with the H2SO4. Reason: Copper is more reactive than hydrogen
ANS: (c) Assertion is true but the Reason is false.
14 In the following questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion. (b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion. 1
(c) Assertion is true but the Reason is false.
(d) The statement of the Assertion is false but the Reason is true. Assertion: Silver becomes black in colour when exposed to atmosphere.
Reason: Silver reacts with H2S gas to form Ag2S which is black in colour.
ANS: (a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
15 The most abundant metal in earth crust is _____________ . 1 ANS: Aluminium
16 If copper is kept open in air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of __________.1
ANS: CuCO3
17 __________ and __________ can be easily cut with knife. 1 ANS: sodium, pottassium
18 Metal reacts with water to give __________ and hydrogen gas. 1 ANS: metal hydroxide
19 When a strip of copper metal is placed in iron(II) sulphate solution, then red-brown copper metal is formed. [True/False] 1 ANS: False
20 When zinc is added to a solution of iron (II) sulphate, then the greenish colour of iron sulphate solution fades gradually due to the formation of colourless zinc sulphate solution and iron is deposited on zinc. [True/False] 1
ANS: True
21 Which of the following two metals will melt at body temperature (37 °C) ?
Gallium, Magnesium, Caesium, Aluminium 1 ANS: Gallium and Caesium
22 From amongst the metals sodium, calcium, aluminium, copper and magnesium, name the metal
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(a) which reacts with water only on boiling, and
(b) another which does not react even with steam.
ANS: (a) Magnesium reacts with water only on boiling.
(b) Copper does not react even with steam.
Write balanced equations for the reaction of :
(a) aluminium when heated in air. Write the name of the product.
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(b) iron with steam. Name the product obtained.
(c) calcium with water. Why does calcium start floating in water ?
ANS: (a) 4Al + 3O2 2Al2O3.
The product formed is aluminium oxide.
(b) 3Fe + 4H2O (Steam) → Fe3O4 + 4H2
The product obtained is iron(II) iron (III) oxide.
(c) Ca + 2H2O → Ca(OH)2 + H2
The bubbles of hydrogen stick to the surface of metal that is why it floats.
24 What is meant by reactivity series of metals? State which of the following chemical reactions will take place giving suitable reason for each.
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(a) Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)
(b) Fe(s) + ZnSO4(aq) → FeSO4(aq) + Zn(s)
(c) Zn(s) + FeSO4(aq) → ZnSO4(aq) + Fe(s)
ANS: Reactivity series is a series of metals arranged in the order of their decreasing reactivities (activities). (a) Reaction will take place because Zn is above Cu in the activity series and is more reactive than Cu. (b) Reaction will not take place as Fe is below Zn in the activity series and cannot displace Zn from its solution. (c) Reaction will take place because Zn is more reactive than Fe.
25 (a) What are amphoteric oxides? Choose the amphoteric oxides from amongst the following oxides: 3
Na2O, ZnO, Al2O3, CO2, H2O
(b) Why is that non-metals do not displace hydrogen from dilute acids?
ANS: (a) Those oxides which are both acidic as well as basic are called amphoteric oxides, e.g. Al2O3, ZnO. (b) It is because non-metals do not supply electrons to change H+ions into hydrogen gas.
26 (a) Write the electron dot structures for potassium and chlorine.
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(b) Show the formation of KCl by the transfer of electrons.
(c) Name the ions present in this compound, KCl.
ANS:
27 (a) Show the formation of Na2O by the transfer of electrons between the combining atoms.
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(b) Why are ionic compounds usually hard?
(c) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state?
ANS: (b) It is due to strong force of attraction between oppositely charged ions. (c) In solid state, ions are not free to move whereas in molten state ions are free to move, therefore, they conduct electricity in molten state.
28 Write one example of each of the following:
(a) Most malleable metal and most ductile metal.
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(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.
ANS: (a) Gold is the most malleable and ductile metal.
(b) Silver is the best conductor, whereas lead is poor conductor of heat.
(c) Tungsten has highest melting point, Mercury has the lowest melting point.
29 Give reasons for the following observations:
(a) Ionic compounds in general have high melting and boiling points.
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(b) Highly reactive metals cannot be obtained from their oxides by heating them with carbon.
(c) Copper vessels get a green coat when left exposed to air in the rainy season.
ANS: (a) Ionic compounds have high melting and boiling points due to strong force of attraction between oppositely charged ions.
(b) It is because these metals, themselves are strong reducing agents. Therefore, cannot be reduced by reducing agent like carbon.
(c) Copper vessels react with CO2, O2 and moisture to form green coloured basic copper carbonate [CuCO3.Cu(OH)2].
30 Explain the following statements:
(a) Most metal oxides are insoluble in water but some of these dissolve in water. What are these
oxides and their solutions in water called?
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(b) At ordinary temperature the surface of metals such as magnesium, aluminium, zinc, etc. is
covered with a thin layer. What is the composition of this layer? State its importance.
(c) Some alkali metals can be cut with a knife.
ANS: (a) Solution of metal oxides in water is called alkali (soluble base), e.g. sodium hydroxide (NaOH), potassium hydroxide (KOH).
(b) This layer is oxide layer. It makes the metal less reactive (passive) and makes it more useful
because it cannot get corroded and remains as it is.
(c) It is because these metals are very soft, e.g. sodium metal can be cut with a knife.
(a) Write electron dot structure for chlorine (At No. 17) and calcium (At No. 20). Show the formation of calcium chloride by the 5
transfer of electrons.
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(b) Identify the nature of the above compound and explain three physical properties of such compounds. ANS: (b) It is ionic compound. Physical properties
1. It is hard and solid.
2. It has high melting and boiling point.
3. It is soluble in water.
32 (a) In the formation of compound between two atoms A and B, A loses two electrons and B gains one electron. (i) What is the nature of bond between A and B ?
(ii) Suggest the formula of the compound formed between A and B.
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(b) On similar lines explain the formation of MgCl2 molecule.
(c) Common salt conducts electricity only in the molten state. Why ?
(d) Why is melting point of NaCl high ?
ANS: (c) Na+ and Cl– are free to move in molten state but not in solid state. (d) It is due to strong force of attraction between Na+ and Cl–.
33 Give reasons for the following:
(a) Silver and copper lose their shine when they are exposed to air. Name the substance formed on their surface in each case. 5
(b) Tarnished copper vessels are cleaned with tamarind juice.
(c) Aluminium is more reactive than iron yet there is less corrosion of aluminium as compared to iron when both are exposed to air.
ANS: (a) These metals get corroded. Silver forms black Ag2S (silver sulphide) and copper form greenish layer of basic copper carbonate CuCO3.Cu(OH)2.
(b) Tamarind contains acid which reacts with basic copper carbonate and product gets dissolved and removed from copper vessel.
(c) Aluminium forms oxide layer on its surface which does not further react with air.
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