CBSE Class 10 Chemistry Metals and Non Metals Worksheet Set A

MULTIPLE CHOICE QUESTIONS

Question. Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same?
(i) Good thermal conductivity
(ii) Good electrical conductivity
(iii) Ductility
(iv) High melting point
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (i) and (iv)
Answer. D

Question. The most abundant metal in the earth’s crust is
(a) Iron
(b) Aluminium
(c) Calcium
(d) Sodium
Answer. B

Question. The poorest conductor of heat among metals is
(a) Lead
(b) Mercury
(c) Calcium
(d) Sodium
Answer. A

Question. Which property of metals is used for making bells and strings of musical instruments like Sitar and Violin?
(a) Sonorousness
(b) Malleability
(c) Ductility
(d) Conductivity
Answer. A

Question. Al₂O₃ + 2NaOH → …… + H₂O
(a) Al(OH)₃
(b) Na₂O
(c) NaAlO₂
(d) AlNaO₂
Answer. C

Question. Which of the following is the correct arrangement of the given metals in ascending order of their reactivity?
Zinc, Iron, Magnesium, Sodium
(a) Zinc > Iron > Magnesium > Sodium
(b) Sodium > Magnesium > Iron > Zinc
(c) Sodium > Zinc > Magnesium > Iron
(d) Sodium > Magnesium > Zinc > Iron
Answer. D

Question. Which of the following pairs will give dis-placement reactions?
(a) FeSO₄ solution and Copper metal
(b) AgNO₃ solution and Copper metal
(c) CuSO₄ solution and Silver metal
(d) NaCl solution and Copper metal
Answer. B

Question. Non-metals form covalent chlorides because
(a) they can give electrons to chlorine
(b) they can share electrons with chlorine
(c) they can give electrons to chlorine atoms to form chloride ions
(d) they cannot share electrons with chlorine atoms
Answer. B

Question. Which of the following oxide(s) of iron would be obtained on prolonged reaction of iron with steam?
(a) FeO
(b) Fe₂O₃
(c) Fe₃O₄
(d) Fe₂O₃ and Fe₂O₄
Answer. C

Question. 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)
Answer. B

Question. The electronic configuration of three elements X, Y and Z are as follows: X = 2, 4 Y = 2, 7
Z = 2,1 Which two elements will combine to form an ionic compound and write the correct formula,
(a) X2Y
(b) ZY
(c) XZ3
(d) Y2Z
Answer. B

Question. Which of the following non-metal is lustrous?
(a) Sulphur
(b) Oxygen
(c) Nitrogen
(d) Iodine
Answer. D

Question. The atomic number of an element ‘X’ is 12. Which inert gas is nearest to X?
(a) He
(b) Ar
(c) Ne
(d) Kr
Answer. C

Question. Example of an amphoteric oxide is:
(a) Na₂O
(b) K₂O
(c) Al₂O₃
(d) MgO
Answer. C

Question. Which one among the following is an acidic oxide?
(a) Na₂O
(b) CO
(c) CO₂
(d) Al₂O₃
Answer. C

Question. Composition of aqua-regia by volume is :
(a) Dil HCl (3) : Cone HNO₃ (1)
(b) Cone HCl (3) : Dil HNO₃ (1)
(c) Cone HCl (3) : Cone HNO₃ (1)
(d) Dil HC1 (3) : Dil HNO₃
Answer. C

Question.  Galvanisation is a method of protecting iron from rusting by coating with a thin layer of
(a) Gallium
(b) Aluminium
(c) Zinc
(d) Silver
Answer. C

Question. An element X 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
(a) Mg
(b) Na
(c) P
(d) Ca
Answer. B

Question. 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
(b) Has low melting point
(c) Conducts electricity in molten state
(d) Occurs as solid
Answer. B

Question. 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 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
Answer. D

 

ASSERTION AND REASON QUESTIONS:

DIRECTION: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.
(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.

Question. Assertion: Al₂O₃, is an amphoteric oxide.
Reason: Al₂O₃ reacts with acid as well as base to form salt and water.
Answer. A

Question. Assertion: Nitrogen is a non-metal.
Reason: Nitrogen has 5 valence electrons.
Answer. B

Question. Assertion: Copper does not reacts with the H2SO4.
Reason: Copper is more reactive than hydrogen.
Answer. C

Question. Assertion: Silver becomes black in colour when exposed to atmosphere.
Reason: Silver reacts with H₂S gas to form Ag₂S which is black in colour.
Answer. A

Question. Assertion: iron is found in the free state in nature.
Reason: iron a highly reactive element.
Answer. D

Question. Name the non-metal which is lustrous?
Answer. Iodine

Question. What is meant by Calcination?
Answer. The carbonate ores are changed into oxides by heating strongly in limited air. This process is known as calcination.

Question. What do you understand by the term Corrosion?
Answer. Corrosion is the deterioration of a material

Question. What is metallurgy?
Answer. The extraction of metals from their ores and then refining them for use is known as metallurgy

Question. 2HgO(s) → 2Hg(l) + O₂ (g).
Name the type of reaction shown in the given chemical equation?
Answer. Reduction

Question. Arrange the following in the increasing order of reactivity.
Mg, K, Al, Cu
Answer. Cu, Al, Mg ,K

Question. Why metals are generally used for making cooking utensils?
Answer. Good conductor of heat

Question. A student used a hammer, beat two objects
a) Wooden table
b) Steel plate. What do you observe in this case?
Answer. Steel plate – Ringing sound

Question. It is said that Al utensils should not be used for cooking as it is toxic for our health. Still we use them but it does not cause any harm to us. Why?
Answer. Al oxide coat is formed over Al

Question. Mg ribbon is burnt then you get ashes, if we dissolve it in water and dip litmus paper. What will we observe?
Answer. Red litmus converts to Blue

Question. Why carbon is not used for extraction of Al from its ore? Which method is used to obtain Al?
Answer. Because carbon has less affinity for Al.
Electrolytic reduction

Question. Why hydrogen gas is not evolved when a metal reacts with HNO₃ ?
Answer. Because HNO₃ is strong oxidizing agent

Question. What will be the electronic configuration of Na atom if we remove one electron from its outermost shell?
Answer.2,8

Question. In the earth’s crust, metals are present in the form of minerals and there are more than one mineral for a particular metal. However, metal may not be extracted from all of them. Why?
Answer. Because it is not profitable to extract

Question. A student has taken NaCl in two forms a) Powdered NaCl b) NaCl solution. In which case will the electricity be conducted and why?
Answer. NaCl solution because of movement of electrons

Question. What would you observe when two metals namely Zn and Cu is added in two test tube containing FeSO4 solution?
Answer. Zn will displace iron

Question. A student put an iron knife kept in blue copper sulphate solution activity. Explain.
Answer. Iron displace Cu from its solution.

Question. An athlete won a bronze medal in a race competition. After some days, he fo its lustre due to the formation of a greenish layer on it. Name the metals present in the medal. What is the reason for the appearance of a greenish layer on its surface ?
Answer. Cu and Sn, Corrosion

Question. What happens if we bring Na metal in contact of water?
Answer. Catches fire

Question. A student set up the following electrolytic refining apparatus in the laboratory strip to cathode and impure Cu strip to anode . After few hours he saw that the set up What could be the possible causes?

Answer. Because he wrongly placed the anode and cathode rod

Question. Evaluate the nature of Zinc oxide from the following given reactions.

Answer. Amphoteric in nature

Question. Two students set up an electric circuit in the lab. One of them used Cu connecting wires and another students used alloy of Cu and Sn as connecting wires. Whose circuit will work more efficiently and why?
Answer. Alloys is poor conductor of electricity. Cu wire circuit will work more efficiently

1. A metal ‘X’ combines with a non-metal ‘Y’ by the transfer of electrons to form a compound Z.

Question. State the type of bond in compoundZ.
Answer. Ionic bond

Question. What can you say about the melting point and boiling point of compound Z?
Answer. High M.P and B.P

Question. Will this compound dissolve in kerosene or petrol?
Answer. No

Question. Which of the following are not ionic compounds?
KCl (ii)HCl (iii)CCl₄ (iv)NaCl
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iii)
Answer. B

Question. (i)Identify the oxides from the following which turn blue litmus into red.
CO₂, Na₂O, CaO, SO₂, NO₂.
(ii)What is the nature of these oxides ?
Answer. CO₂, SO₂, NO₂. – Acidic oxides

Question. Metallic compound A reacts with dilute hydrochloric acid to produce effervescence and a gas B. The gas B extinguishes a burning candle and also turns lime water milky. Identify A and B. Write balanced chemical equations for the reactions involved.
Answer. NaHCO₃ – A
CO₂ – B

2. Alloying is a very good method of improving the properties of a metal. We can get the desired properties by this method. For example, iron is the most widely used metal. But it is never used in its pure state. This is because pure iron is very soft and stretches easily when hot. But, if it is mixed with a small amount of carbon (about 0.05 %), it becomes hard and strong. When iron is mixed with nickel and chromium, we get stainless steel, which is hard and does not rust. Thus, if iron is mixed with some other substance, its properties change. In fact, the properties of any metal can be changed if it is mixed with some other substance. The substance added may be a metal or a non-metal.

Question. Alloy is …………………………. Type of mixture.
Homogenous
Heterogenous
Colloid
None of the above
Answer.A

Question. If one metal is Mercury then the alloy is known as……..
Brass
Bronze
Amalgam
Steel
Answer.C

Question. Name the metal which is mixed with the Gold to make it suitable for making jewellary?
Copper
Silver
Both A and B
Iron
Answer.C

Question. An alloys is made by dissolving different elements in any ratio. State whether the statement is True/False.
Metals react with water and produce a metal oxide and hydrogen gas. Metal oxides that are soluble in water dissolve in it to further form metal hydroxide. But all metals do not react with water
Metal + Water → Metal oxide + Hydrogen
Metal oxide + Water → Metal hydroxide
Answer. False

Question. What happens when calcium is reacts with water?
It does not react with water
It reacts violently with water
It reacts less violently with water
Bubbles of hydrogen gas formed stick to the surface of calcium
(a) (i) and (iv)
(b) (ii) and (iii)
(c) (i) and (ii)
(d) (iii) and (iv)
Answer. D

Question. Mg reacts with hot water to form MgO and H2. Which of the following statements are true?
Mg(OH)₂ turns blue litmus red
H2 released in the rection burns with a pop sound
Mg(OH)₂ formed during the reaction floats on the surface of water
Mg also reacts with cold water
A and B
B and C
B, C and D
A, B, C
Answer.B

Question.  Show the formation of NaCl by transfer of electron. And name the cation and anion formed during the reaction?
Answer. Na+ Cl-

3. Different metals show different reactivities towards oxygen. Metals such as potassium and sodium react so vigorously that they catch fire if kept in the open. Hence, to protect them and to prevent accidental fires, they are kept immersed in kerosene oil. At ordinary temperature, the surfaces of metals such as magnesium, aluminium, zinc, lead, etc., are covered with a thin layer of oxide. Iron does not burn on heating but iron filings burn vigorously when sprinkled in the flame of the burner. Copper does not burn, but the hot metal is coated with a black coloured layer. Silver and gold do not react with oxygen even at high temperatures. What is the role of thin layer of oxide formed over the surface of Mg.

Question. Iron does not burn on heating but iron filings burn vigorously when sprinkled in the flame of the burner.
Why?
What is the chemical name of the black coloured layer formed over Cu when it is heated?
Answer.A) Prevents the metal from further oxidation.
B) iron fillings when sprinkled in flames attain the ignition temperature (as iron fillings are comparatively smaller particles) and gain larger surface area for the reaction. Therefore they burn vigorously.
C) Copper carbonate

4. A familiar example of an ionic compound is table salt or sodium chloride. Salt has a high melting point of 800ºC. While a salt crystal is an electric insulator, saline solutions (salt dissolved in water) readily conduct electricity. Molten salt is also a conductor. If you examine salt crystals with a magnifying glass, you can observe the regular cubic structure resulting from the crystal lattice. Salt crystals are hard, yet brittle --
it's easy to crush a crystal. Although dissolved salt has a recognizable flavor, you don't smell solid salt because it has a low vapor pressure.

Question.Why ionic compounds have high Melting point?
Answer. Because iterionic bond is very strong

Question.Why can’t Na accept electrons from Cl to form NaCl?
Answer. Na need to complete its outermost orbital. For Na it is not energy feasible.

Question. Suppose if Na donates two electrons to Cl. How will it affect Na ion?
Answer. Stability disturb

5. The metals in the middle of the activity series such as iron, zinc, lead, copper, etc., are moderately reactive. These are usually present as sulphides or carbonates in nature. It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates. Therefore, prior to reduction, the metal sulphides and carbonates must be converted into metal oxides.

Suggest a method of reduction for the following metals during their metallurgical processes:

Question. metal ‘A’ which is one of the last, second or third position in the reactivity.
Answer. Oxidation, by heating its metallic oxide

Question. metal ‘B’ which gives vigorous reaction even with water and air.
Answer. Electrolytic refining

Question. metal ‘C’ which is kept in the middle of activity series.
Answer. Roasting and calcination

6. Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. It is caused by a chemical reaction that affects masses of iron and steel.Once formed, rust begins to eat away at the metal, forming a flaky, orange-red coating that weakens the iron.

Question. Write a chemical equation for rusting?
Answer. 4Fe + 3O₂ + 2xH₂O → 2Fe₂O₃ .xH₂O

Question. Write the measures taken for prevention of rusting?
Answer.  Galvanisation , Painting, Anodising , Greese and oiling etc

Question. Why rusting takes place very fast near coastal areas?
Answer. Due to high content of minerals and water which is suitable for rusting

Question. Silver articles become black after some time when exposed to air. Why?
Answer. Due to corrosion

Question. Can rusting be also called Corrosion?
Answer. Yes , rusting is a type of corrosion

 

Question. Name two metals which catch fire if kept in open air.
Answer. Sodium and Potassium

Question. Which of the following metals neither reacts with cold nor with hot water?
Sodium, Magnesium, Zinc, Iron, Calcium
Answer. Zinc and Iron

Question. Name two metals which can form hydrides with hydrogen.
Answer. Sodium and Calcium

Question. Name the element which shows non-metallic properties but is also present in the activity series of metals.
Answer. Hydrogen

Question. What is rust ? Write its chemical formula.
Answer. Rust is brown, flaky substance. Its chemical formula is Fe₂O₃.xH₂O

 

SHORT ANSWER TYPE QUESTIONS

Question. A non-metal X exists in different forms Y and Z. Y is the hardest natural substance, whereas Z is a good conductor of electricity. Identify X, Y and Z.
Answer. X –Carbon, Y – Diamond, X – Graphite

Question. State reasons for the following:
(i) Electric wires are covered with rubber-like material.
(ii) From dilute hydrochloric acid, zinc can liberate hydrogen gas but copper cannot.
Answer.  (i) It is because rubber is an insulator and does not allow current to flow through it.
(ii) Zinc is is placed above hydrogen in the reactivity series of metals while copper is placed below it. Metals placed above hydrogen can displace hydrogen from water and acids while those below it cannot. Therefore, zinc can displace hydrogen from dilute HCl whereas copper cannot.

Question. Give the formulae of the stable binary compounds that would be formed by the combination of the following pairs of elements.
(a) Mg and N₂
(b) Li and O₂
(c) Al and Cl₂
(d) K and O₂
Answer. (a) Mg₃N₂ (b) Li₂O (c) AlCl₃ (d) K₂O

Question. Name any one metal which reacts neither with cold water nor with hot water, but reacts with heated steam to produce hydrogen gas.
Answer. Iron
3Fe (s) + 4H₂O (g) → Fe₃O₄ (s) + 4H₂ (g)

Question. Complete the chemical equation.

Answer.

 

LONG ANSWER TYPE QUESTIONS
 

Question. Explain how the following metals are obtained from their compounds by reduction process:
(i) Metal X which is low in reactivity series
(ii) Metal Y which is in the middle of the series
Give one example of each type.
Answer. (i) Metals which are low in reactivity series can be obtained by heating their compounds. For example, mercury is obtained by heating its ore, cinnabar (HgS), in air.
HgS + O₂ → Hg + SO₂
(ii) Metals which are in the middle of the series are generally obtained by heating their compounds with some reducing agent such as carbon. For example, iron is obtained from haematite (Fe₂O₃) by reduction with carbon.
2Fe₂O₃ + 3C → 4Fe + 3CO₂

Question. Explain the following:
(a) Reactivity of Al decreases if it is dipped in cone. HNO₃
(b) Carbon cannot reduce the oxides of Na or Mg.
(c) NaCl is not a conductor of electricity in solid state whereas it does conduct electricity in aqueous solution as in molten state
(d) Iron articles are galvanised.
Answer. (a) When Al metal is dipped in cone. HNO3 for sometime, it is oxidised initially to aluminium oxide (Al₂O₃). The oxide gets deposited on the surface of the metal and forms a protective coating on the surface. The metal is said to become passive towards air, acids and alkalies. Its reactivity therefore, decreases.
(b) Both Na and Mg are more reactive than carbon. Therefore, carbon is not in a position to reduce the oxides of these metals.
(c) NaCl is an ionic compound. Its electrical conductivity is due to the mobility of Na+ and Cl– ions.
These ions cannot move in the solid state. However, they can do so either in molten state of the salt or when it forms and aqueous solution in water.
(d) Iron has a tendency to get rusted in atmosphere by reacting with oxygen and water vapours present in air. In order to check rusting, iron articles are generally coated with zinc. This process is known as galvanization.

 

LONG ANSWER TYPE QUESTIONS

Question. A metal E is stored under kerosene. When a small piece of it is left open in air, it catches fire.
When the product formed is dissolved in water, it turns red litmus to blue.
(i) Name the metal E.
(ii) Write the chemical equation for the reaction when it is exposed to air and when the product is dissolved in water.
(iii) Explain the process by which the metal E is obtained from its molten chloride.
Answer. (i) The available information suggests that the metal (E) is sodium (Na).

The solution is basic and it turns red litmus blue.
(iii) The metal is obtained by the process of electrolytic reduction.

Question. A student has been collecting silver coins and copper coins. One day, she observed a black coating on silver coins and a green coating on copper coins. Which chemical phenomenon is responsible for these coatings? Write the chemical name of black and green coatings.
Answer. The name of the phenomenon is corrosion. The chemical name of black coating is silver sulphide (Ag₂S) formed due to attack of H2S gas present in the atmosphere on silver and that of green coating is basic copper carbonate formed due to attack of moist air (CO₂, O₂ and H₂O vapours) on copper.

Question. (a) Name the main ore of mercury. How is mercury obtained from its ore?
(b) Give balanced chemical equation.
(c) What is thermite reaction? How is it used to join the railway tracks or cracked machine parts?
(d) Name the method used to extract metals of high reactivity.
Answer. (a) Cinnabar
(b)Mercury is obtained from its ore by roasting.
HgS + O₂ → Hg + SO₂
(c) When aluminium is heated with Fe₂O₃ to get molten iron, it is called thermite reaction.
Fe₂O₃ + 3Al → Al₂O₃ + 2Fe
Molten iron is used to weld broken railway tracks.
(d) Electrolytic reduction