metals and non metals Quiz-Class X

Metals And Non-metals : Important Questions

Metals And Non-metals

Question: Name one metal and one non-metal which exist in liquid state at room temperature

Solution: Metal is Mercury and Non metal is Bromine

Question : Why are metals called electropositive elements where as non-metals are called electronegative elements?

Solution: Metals are electropositive elements because they can form positive ions by losing electrons whereas Non-metals are electronegative elements because they can form negative ions by gaining electrons .

Question : Name the most abundant metal in the earth's crust .

Solution: Aluminium

Question : Name the most abundant non-metal in the earth's crust .

Solution : Oxygen

Question : Name one metal which has a low melting point .

Solution: Cesium

Question : Name the metal which is the poorest conductor of heat .

Solution: Lead

Question : From amongst the metals sodium, calcium, aluminium, copper and magnesium, name the metal : (i ) which reacts with water only on boiling (ii ) which does not react even with steam.

Solution (i) Aluminium. (ii ) Copper.

Question : What is aqua-regia? Name two special metals which are insoluble in common reagents but dissolve in aqua-regia.

Solution: Aqua-regia is a freshly prepared mixture of one part of concentrated nitric acid and 3 parts of concentrated hydrochloric acid.
Gold and platinum dissolve in aqua-regia .

Question : Give the names and formulae of (a) two acidic oxides, and (b) two basic oxides.

Solution: (a) Carbon dioxide and sulphur dioxide. (b) Sodium oxide and magnesium oxide.

Question : What name is given to those metal oxides which show basic as well as acidic behavior?

Solution: Amphoteric oxides.

Question : Name two metals which form amphoteric oxides.

Solution: Aluminium and zinc.

Question : A copper coin is kept immersed in a solution of silver nitrate for some time. What will happen to the coin and the colour of the solution?

Solution: Copper coin will get a shining grayish white coating of silver metal. The color of the solution will turn blue.

Question : Which property of copper and aluminium makes them suitable: (a) for making cooking utensils and boilers ? (b) for making electric wires ?

Solution: (a) High thermal conductivity. (b) High electrical conductivity.

Question : Write the names and formulae of (a) a metal hydride, and (b) a non-metal hydride.

Solution: (a) Sodium hydride, (b ) Hydrogen sulphide

Question : Name the metal which has been placed (a) at the bottom of the reactivity series (b) at the top of the reactivity series (c) just below copper in the reactivity series

Solution: (a) Gold. (b) Potassium. (c) Mercury.

Question : Which of the two metals is more reactive: copper or silver?

Solution: Copper

Question : (a) Name one metal which is stored in kerosene oil. (b) Name one non-metal which is stored under water.

Solution: (a) Sodium (b) White phosphorus.

Question : Write equation for the reaction of: (a) sodium with oxygen (b) magnesium with oxygen

Solution: (a) 4Na(s) + O₂(g) → 2Na₂O(s)

(b ) 2Mg(s) + O₂(g) → 2MgO(s)

Question : Name two metals which are used: (a) for making electric wires. (b) for making domestic utensils and factory equipment. (c) for making jewellery and to decorate sweets.

Solution: (a) Aluminium and copper (b) Copper and aluminium (c) Gold and silver.

Question : Which metal foil is used for packing some of the medicine tablets?

Solution : Aluminium foil.

Question : Name the non-metal which is used: (a) to convert vegetable oil into vegetable ghee(solid fat). (b) as a rocket fuel (in liquid form). (c) to make electrodes of dry cells. (d) to preserve food materials. (e) in the vulcanization of rubber.

Solution : (a) Hydrogen (b) Hydrogen. (c) Carbon (d) Nitrogen. (e) Sulphur.

Question : Name one property which is characteristic of (a) metals, and (b) non-metals.

Solution: (a) Metals are malleable (b) Non-metals are non-malleable

Question : What is meant by "brittleness ? Which type of elements usually show brittleness: metals or non-metals?

Solution: Brittleness is the property of being brittle i.e. breaking easily. Non-metals show brittleness.

Question : What will happen if a strip of zinc is immersed in a solution of copper sulphate?

Solution: When a strip of zinc metal is put in copper sulphate solution, then the blue colour of copper sulphate solution fades gradually and red brown coating of copper is deposited on zinc strip.

Question : What will happen if a strip of copper is kept immersed in solution of silver nitrate (AgNO3)?

Solution: When a strip of copper metal is immersed in silver nitrate solution, the solution gradually becomes blue and a shining greyish-white deposit of silver metal is formed on copper strip.

Question : What happens when iron nails are put into copper sulphate solution?

Solution: When iron nails are placed in copper sulphate solution, the blue colour of copper sulphate solution fades gradually and red-brown copper metal is formed.

Question : How would you show that silver is chemically less reactive than copper?

Solution : If a strip of silver metal is kept immersed in copper sulphate solution for some time, then no reaction occurs. This shows that silver is not able to displace copper from copper suphate solution.

Question : why Blue colour of copper sulphate solution is destroyed when iron filings are added to it.

Solution: Blue color of copper sulphate is destroyed because iron displaces copper from copper sulphate solution as iron is more reactive than copper.

Question : Name a non-metal having a very high melting point.

Solution: Diamond.

Question : Which property of graphite is utilized in making electrodes? Solution: Since graphite is a good conductor of electricity, it is used in making electrodes

Question : Name two non-metals which are both brittle and non-ductile. Solution: Sulphur and phosphorus.

Question : Explain why, the surface of some metals acquires a dull appearance when exposed to air for a long time .

Solution: The surface of some metals acquires a dull appearance when exposed to air for a long time because metals form a thin layer of oxides, carbonates or sulphide on their surface by the slow action of various gases present in air.

Question: What is meant by saying that the metals are malleable and ductile ? Explain with examples .

Solution: Metals are malleable i.e. they can be beaten into thin sheets with a hammer. Example: Aluminium.

Metals are ductile i.e. they can be drawn into thin wires. Example: Copper.

Question : Name two metals which are both malleable and ductile.

Solution: Aluminium and copper.

Question : Which property of iron metal is utilized in producing iron sheets required for making buckets?

Solution: Malleability

Question :Which property of copper metal is utilized in making thin wires?

Solution: Ductility

Question : Name two metals which react violently with cold water. Write any three observations you would make when such a metal is dropped into water. How would you identify the gas evolved, if any, during the reaction?

Solution: Sodium and potassium metals react violently with cold water.
Observations: 1. Metal starts moving over the surface of water making a hissing sound.
Observations: 2. Metal starts reacting with water causing little explosions.

Observations: 3 . Soon the metal catches fire and starts burning.

Question : What are amphoteric oxides? Give two examples of amphoteric oxides.

Solution: Those metal oxides which show basic as well as acidic behavior are known as amphoteric oxides . Example: Aluminium oxide and zinc oxide.

Question : Choose the acidic oxides, basic oxides and neutral oxides from the following

Na₂O, CO₂ CO , SO₂, MgO, H₂O, N₂O

Solution:
Acidic oxide : CO₂, CO, SO₂and N₂O
Basic oxide : Na₂O, MgO;
Neutral oxide : H₂O

Question : What is the nature of the oxide SO₂? What happens when it is dissolved in water? Write the chemical equation of the reaction involved.

Solution: SO₂ is acidic in nature. When dissolved in water, it produces sulphurous acid.

SO₂ (g) + H₂O (l) → H₂SO₃(aq)

Question : What is the nature of the oxide Na₂O ? What happens when it is dissolved in water? Write the chemical equation of the reaction inolved.

Solution: Na₂O is basic in nature. When dissolved in water, it forms an alkali called sodium hydroxide.

Na₂O (s) + H₂O → 2NaOH(aq)

Question : Explain why, metals usually do not liberate hydrogen gas with dilute nitric acid.

Solution: Metals do not liberate hydrogen gas with nitric acid because nitric acid is a strong oxidizing agent. So, as soon as hydrogen gas is formed in the reaction between a metal and dilute nitric acid, the nitric acid oxidizes this hydrogen to water.

Question : Name two metals which can, however, liberate hydrogen gas from very dilute nitric acid.

Solution: Magnesium and manganese.

Question : How do metals react with hydrogen ? Explain with an example.

Solution : Most of the metals do not react with hydrogen. Only a few reactive metals react with hydrogen to form metal hydrides. For example: When hydrogen gas is passed over heated sodium, then sodium hydride is formed.

2Na + H₂ → 2NaH

Question : How do non-metals react with hydrogen ? Explain with an example.

Solution : Non-metals react with hydrogen to form covalent hydrides. For example: Sulphur combines with hydrogen to form hydrogen sulphide .

Question : What happens when calcium reacts with chlorine ? Write an equation for the reaction which takes place.

Solution: Calcium reacts vigorously with chlorine to form an ionic chloride called calcium chloride.

Ca + Cl₂ → CaCl₂

Question :What happens when magnesium reacts with very dilute nitric acid ? Write an equation for the reaction involved.

Solution :Magnesium reacts with very dilute nitric acid to form magnesium nitrate and hydrogen gas.

Mg(s) + HNO₃(aq) → Mg(NO₃)₂(aq) + H₂(g)

Question: Arrange the following metals in order of their chemical reactivity, placing the most reactive metal first: Magnesium, Copper, Iron, Sodium, Zinc, Lead, Calcium.

Solution: Sodium > Calcium > Magnesium > Zinc > Iron > Lead > Copper

Question : What happens when a rod of zinc metal is dipped into a solution of copper sulphate ? Give chemical equation of the reaction involved .

Solution : When a strip of zinc metal is put in copper sulphate solution, then the blue colour of copper sulphate solution fades gradually and red brown coating of copper is deposited on the zinc strip.

Zn(s) + CuSO₄(aq) → ZnSO₄(aq) + Cu(s )

Question : A copper plate was dipped in AgNO₃ . After certain time, silver from the solution was deposited on the copper plate. State the reason why it happened. Give the chemical equation of the reaction involved.

Solution: Silver gets deposited on the copper plate because copper is more reactive than silver and hence displaces silver from silver nitrate solution .

2AgNO₃ (aq) + Cu(s) → Cu( NO₃ )₂ (aq) + 2Ag(s)

Question : State five uses of metals and five of non-metals

Solution:

Uses of metals:

Lead metal is used in making car batteries.
Zinc is used for galvanizing iron to protect it from rusting.
Iron, copper and aluminium are used to make utensils.
Copper and aluminium metals are used to make electrical wires.
Aluminium is used to make aluminium foil for packaging materials.

Uses of non-metals:

Hydrogen is used in the hydrogenation of vegetable oils.
Carbon is used to make electrodes of electrolytic cells and dry cells.
Nitrogen is used in the manufacture of ammonia, nitric acid and fertilizers.
Sulphur is used for producing sulphuric acid.
Liquid hydrogen is used as rocket fuel.

Question : State one use each of the following metals: Copper, Aluminium, Iron, Silver, Gold, Mercury

Solution:
Copper : Copper is used to make wires to carry electric current.
Aluminium: Aluminium foils are used in packaging of food materials.
Iron : Iron is used to make utensils.
Silver : Silver is used to make jewellery.
Gold: Gold is used to make jewellery.
Mercury : Mercury is used in thermometers.

Question : (a) State one use each of the following non-metals: Hydrogen, Carbon (as Graphite), Nitrogen, Sulphur (b) Name the metal which is used in making thermometers.

Solution: (a)
Hydrogen : Hydrogen is used in the hydrogenation of vegetable oils.
Carbon : Carbon is used to make electrodes of electrolytic cells and dry cells.
Nitrogen : Nitrogen is used in the manufacture of ammonia, nitric acid and fertilizers.
Sulphur : Sulphur is used in making sulphuric acid.

(b) Mercury

Question : Why does aluminium not react with water under ordinary conditions?

Solution: Aluminium metal does not react with water under ordinary conditions because of the presence of a thin layer of aluminium oxide on its surface.

Question : Name two metals which can displace hydrogen from dilute acids. Solution : Sodium and magnesium.

Question : Why is sodium kept immersed in kerosene oil?

Solution : Sodium is a very reactive metal so it reacts vigorously with the oxygen of air and catches fire. It is kept immersed in kerosene oil to protect it from the action of oxygen, moisture and carbon dioxide of air and to prevent accidental fires.

Question : Why is white phosphorus kept immersed under water ?

Solution : White phosphorus is kept immersed in water because it reacts spontaneously with oxygen of air to form phosphorus pentoxide but does not react with water.

Question : Can we keep sodium immersed under water ? Why ?

Solution : No, because sodium reacts vigorously with water to form sodium hydroxide and hydrogen.

Question : Describe the reaction of potassium with water. Write the equation of the reaction involved.

Solution: Potassium reacts violently with cold water to form potassium hydroxide and hydrogen gas.

K(s) + 2H₂O ( l ) → 2KOH(aq) + H₂(g) + Heat

Question : Write an equation of the reaction of iron with steam. Indicate the physical states of all the reactants and products.

Solution : 3Fe(s)+ 2H₂O(l) → Fe₃O₄(s) + H₂ ( g )

Question : What is the action of water on (a) sodium (b) magnesium, and (c) aluminium ? Write equations of the chemical reactions involved.

Solution:
(a) Sodium reacts vigorously with cold water forming sodium hydroxide and hydrogen gas

2Na(s) + 2H₂O( l ) → 2NaOH(aq) + H2(g) + Heat

(b) Magnesium reacts with hot water to form magnesium hydroxide and hydrogen

Mg(s) + 2H₂O ( l ) → Mg(OH)2 (aq) + H2 (g)

2Al(s) + 3H₂O ( l ) → Al₂O₃ (s) +3H ₂

Question : You are given samples of three metals: sodium, magnesium and copper. Suggest any two activities to arrange them in order of their decreasing reactivity.

Solution:
Activity 1 : When sodium, magnesium and copper are left in air, sodium reacts vigorously with oxygen to form sodium oxide, magnesium reacts with oxygen to form magnesium oxide only on heating, whereas copper does not burn in air even on strong heating. It reacts only on prolonged heating. This shows that sodium is most reactive, then magnesium and copper is the least reactive among the three.
Activity 2 : Sodium reacts vigorously with cold water to form sodium hydroxide and hydrogen, magnesium does not react with cold water but reacts with hot water to form magnesium hydroxide and hydrogen but copper does not react even with steam. This shows that sodium is highly reactive; magnesium is less reactive than sodium and copper is the least reactive among the three.

Question : Write one reaction in which aluminium oxide behaves as a basic oxide and another in which it behaves as an acidic oxide.

Solution: Al₂O₃(s) + HCI (aq) → 2AICl₃ (aq)+ 3H₂O

In this reaction, aluminium oxide behaves as a basic oxide because it reacts with an acid to form salt and water.

Al₂O₃(s) + 2NaOH (aq) → 2NaAlO₂ (aq) + H₂O

In this reaction, aluminium oxide behaves as an acidic oxide because it reacts with a base to form salt and water.

Question : What special name is given to substances like aluminium oxide.

Solution: Amphoteric oxides

Question : Name another metal oxide which behaves like aluminium oxide.

Solution: Zinc oxide

Question : What happens when calcium reacts with water ? Write the chemical equation of the reaction of calcium with water.

Solution: Calcium reacts with cold water to form calcium hydroxide and hydrogen gas.

Ca(s) + H₂O → Ca(OH )₂(aq) + H₂ (g)

Question : Write the chemical equation of the reaction which takes place when iron reacts with dilute sulphuric acid. What happens when the gas produced is ignited with a burning matchstick?

Solution : When iron reacts with dilute sulphuric acid, it forms iron sulphate and hydrogen gas.

Fe(s) + H₂SO₄(aq) → FeSO₄ (aq) + H₂ (g)

When hydrogen gas is ignited with a burning matchstick, it produces a 'pop' sound.

Question : You are given a dry cell, a torch bulb with holder, wires and crocodile clips. How would you use them to distinguish between samples of metals and non-metals?

Solution: We would create an apparatus using dry cell, a torch bulb fitted in a holder and some connecting wires with crocodile clips and connect them to make an electric circuit. Then insert a piece of sulphur between the crocodile clips and the bulb does not light up at all. This means that sulphur does not allow the electric current to pass through it. Now insert a piece of copper between the crocodile clips and the bulb will light up. This observation shows that non metals (ex-sulphur) do not conduct electricity and metals (ex-copper) conduct electricity.

Question : State any five physical properties of metals and five physical properties of non-metals

Solution:
Properties of metals:
Metals are malleable i.e. they can be beaten into thin sheets with a hammer.
Metals are ductile i.e. they can be drawn into thin wires.
Metals are good conductors of heat and electricity.
Metals are lustrous. (v) Metals are generally hard.

Properties of non-metals
Non-metals are non-malleable i.e. they cannot be beaten into thin sheets with a hammer.
Non-metals are non-ductile i.e. they cannot be drawn into thin wires.
Non-metals are bad conductors of heat and electricity.
Non-m etals are non- lustrous.
Non-metals are generally soft

Question : Name two physical properties each of sodium and carbon in which their behaviour is not as expected from their classification as metal and non-metal respectively.

Solution: Sodium metal: Soft, low melting point Carbon non-metal: graphite conducts electricity, diamond has a very high melting point

Question : Name two metals whose melting points are so low that they melt when held in the hand.

Solution: Gallium and cesium

Question : Metals are said to be shiny. Why do metals generally appear to be dull? How can their brightness be restored?

Solution: Metals lose their shine or brightness on keeping in air for a long time and acquire a dull appearance due to the formation of a thin layer of oxide, carbonate or sulphide on their surface by the slow action of various gases present in air . Brightness of metals can be restored by rubbing the dull surface of the metal object with a sand paper, then the outer corroded layer is removed and the metal object becomes shiny and bright once again.

Question : What are metals ? Name five metals.

Solution: Metals are the elements that conduct heat and electricity, and are malleable and ductile. Example: Iron, aluminium, copper, gold and silver.

Question : Name a metal which is so soft that it can be cut with a knife.

Solution : Sodium

Question : Name the metal which is the best conductor of heat and electricity.

Solution :Silver

Question : What happens when a metal reacts with dilute hydrochloric acid ? Explain with the help of an example.

Solution : When a metal reacts with dilute hydrochloric acid, it forms metal chloride and hydrogen gas. Example: Magnesium reacts rapidly with dilute hydrochloric acid to form magnesium chloride and hydrogen.

Mg(s) + 2HCI (aq) → MgCl₂(aq) + H₂ (g)

Question : Define non-metals. Give five examples of non-metals.

Solution: Non-metals are the elements that do not conduct heat and electricity and are neither malleable nor ductile. Example: Carbon, sulphur, phosphorus, silicon and oxygen.

Question : Name a non-metal which conducts electricity.

Solution : Carbon (Graphite)

Question :Name a non-metal having lustre (shining surface).

Solution : lodine

Question : Name a non-metal which is extremely hard.

Solution : Carbon (Diamond)

Question : How do non-metals react with oxygen? Explain with an example. Give equation of the reaction involved. What is the nature of the product formed? How will you demonstrate it?

Solution : Non-metals react with oxygen to form acidic oxides or neutral oxides. Carbon burns in air to form carbon dioxide

The nature of the product formed is acidic.

When carbon dioxide dissolves in water, it forms carbonic acid. It turns blue litmus to red which shows it is acidic in nature.

Question : What is meant by the reactivity series of metals?

Solution: The arrangement of metals in the order of decreasing reactivities is called reactivity series.

order of reactivity:

K > Na >Ca > Mg > Al > Zn > Fe > Pb > Cu > Hg >

Question : Hydrogen is not a metal but still it has been assigned a place in the reactivity series of metals. Why?

Solution : Though hydrogen is not a metal but it has been placed in the reactivity series of metals due to the fact that like metals, hydrogen also loses electrons and forms positive ions.

Question : Name one metal more reactive and another less reactive than hydrogen .
Solution : Lead is more reactive than hydrogen and copper is less reactive than hydrogen.

Question : Name one metal which displaces copper from copper sulphate solution and one which does not.

Solution : Zinc displaces copper from copper sulphate solution and mercury does not displace copper from copper sulphate solution.

Wednesday, June 9, 2021

metals and non metals Quiz-Class X

Metals And Non-metals : Important Questions

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arvind kushwaha