Lesson: Metals and Non-metals

Question 1

Which of the following property is generally not shown by metals?

(a) Electrical conduction

(b) Sonorous in nature

(d) Ductility

Solution:

(c)

Question 2

The ability of metals to be drawn into thin wire is known as:

(a) Ductility

(b) Malleability

(d) Conductivity

Solution:

(a)

Question 3

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)

(d) (i) and (iv)

Solution:

(d)

Question 4

Which one of the following metals does not react with cold as well as hot water?

(a) Na

(b) Ca

(d) Fe

Solution:

(d)

Question 5

Which of the following oxide(s) of iron would be obtained on prolonged reaction of iron with steam?

(a) $F e O$

(b) $F e_{2} O_{3}$

(d) $F e_{2} O_{3} a n d F e_{3} O_{4}$

Solution:

(c)

Question 6

What happens when calcium is treated with water?

(i) It does not react with water

(ii) It reacts violently with water

(iii) It reacts less violently with water

(iv) Bubbles of hydrogen gas formed stick to the surface of calcium

(a) (i) and (iv)

(b) (ii) and (iii)

(d) (iii) and (iv)

Solution:

(d)

Question 7

Generally, metals react with acids to give salt and hydrogen gas.

Which one of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)?

(a) $H_{2} S O_{4}$

(b) $H C l$

(d) All of these

Solution:

(c)

Question 8

The composition of aqua-regia is:

(a) $D i l . H C l : C o n c . H N O_{3}$

$3 : 1$

(b) $C o n c . H C l : D i l . H N O_{3}$

$3 : 1$

(d) $D i l . H C l : D i l . H N O_{3}$

$3 : 1$

Solution:

(c)

Question 9

Which of the following are not ionic compounds?

(i) $K C l$

(ii) $H C l$

(iii) $C C l_{4}$

(iv) $N a C l$

(a) (i) and (ii)

(b) (ii) and (iii)

(d) (i) and (iii)

Solution:

(b)

Question 10

Which one of the following properties is not generally exhibited by ionic compounds?

(a) Solubility in water

(b) Electrical conductivity in solid state

(d) Electrical conductivity in molten state

Solution:

(b)

Question 11

Which of the following metals exist in their native state in nature?

(i) Cu

(ii) Au

(iii) Zn

(iv) Ag

(a) (i) and (ii)

(b) (ii) and (iii)

(d) (iii) and (iv)

Solution:

(c)

Question 12

Metals are refined by using different methods. Which of the following metals are refined by electrolytic refining?

(i) Au

(ii) Cu

(iii) Na

(iv) K

(a) (i) and (ii)

(b) (i) and (iii)

(d) (iii) and (iv)

Solution:

(a)

Question 13

Silver articles become black on prolonged exposure to air. This is due to the formation of:

(a) $A g_{3} N$

(b) $A g_{2} O$

(d) $A g_{2} S a n d A g_{3} N$

Solution:

(c)

Question 14

Galvanisation is a method of protecting iron from rusting by coating with a thin layer of:

(a) Gallium

(b) Aluminium

(d) Silver

Solution:

(c)

Question 15

Stainless steel is very useful material for our life. In stainless steel, iron is mixed with:

(a) Ni and Cr

(b) Cu and Cr

(d) Cu and Au

Solution:

(a)

Question 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:

(a) $C u S O_{4}$

(b) $C u C O_{3}$

(d) $C u O$

Solution:

(b)

Question 17

Generally, metals are solid in nature. Which one of the following metals is found in liquid state at room temperature?

(a) Na

(b) Fe

(d) Hg

Solution:

(d)

Question 18

Which of the following metals are obtained by electrolysis of their chlorides in molten state?

(i) Na

(ii) Ca

(iii) Fe

(iv) Cu

(a) (i) and (iv)

(b) (iii) and (iv)

(d) (i) and (ii)

Solution:

(d)

Question 19

Generally, non-metals are not lustrous. Which of the following non-metal is lustrous?

(a) Sulphur

(b) Oxygen

(d) Iodine

Solution:

(d)

Question 20

Which one of the following four metals would be displaced from the solution of its salts by other three metals?

(a) Mg

(b) Ag

(d) Cu

Solution:

(b)

Question 21

2 mL each of concentrated $H C l$ , $H N O_{3}$ and a mixture of concentrated

$H C l$ and concentrated $H N O_{3}$ in the ratio of 3: 1 were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C respectively. The metal could be:

(a) Al

(b) Au

(d) Pt

Solution:

(b)

Question 22

An alloy is:

(a) An element

(b) A compound

(d) A heterogeneous mixture

Solution:

(c)

Question 23

An electrolytic cell consists of:

(i) Positively charged cathode

(ii) Negatively charged anode

(iii) Positively charged anode

(iv) Negatively charged cathode

(a) (i) and (ii)

(b) (iii) and (iv)

(d) (ii) ad (iv)

Solution:

(b)

Question 24

During electrolytic refining of zinc, it gets:

(a) Deposited on cathode

(b) Deposited on anode

(d) Remains in the solution

Solution:

(a)

Question 25

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:

(a) Mg

(b) Na

(d) Ca

Solution:

(b)

Question 26

Alloys are homogeneous mixtures of a metal with a metal or non-metal. Which among the following alloys contain non-metal as one of its constituents?

(a) Brass

(b) Bronze

(d) Steel

Solution:

(d)

Question 27

Which among the following statements is incorrect for magnesium metal?

(a) It burns in oxygen with a dazzling white flame

(b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas

(d) It reacts with steam to form magnesium hydroxide and evolves hydrogen gas

Solution:

(b)

Question 28

Which among the following alloys contain mercury as one of its constituents?

(a) Stainless steel

(b) Alnico

(d) Zinc amalgam

Solution:

(d)

Question 29

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

(d) Occurs as solid

Solution:

(b)

Question 30

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

(d) Y is a non-metal and Z is a metal

Solution:

(d)

Question 31

Although metals form basic oxides, which of the following metals form an amphoteric oxide?

(a) Na

(b) Ca

(d) Cu

Solution:

(c)

Question 32

Generally, non-metals are not conductors of electricity. Which of the following is a good conductor of electricity?

(a) Diamond

(b) Graphite

(d) Fullerene

Solution:

(b)

Question 33

Electrical wires have a coating of an insulting material. The material, generally used is:

(a) Sulphur

(b) Graphite

(d) All can be used

Solution:

(c)

Question 34

Which of the following non-metals is a liquid?

(a) Carbon

(b) Bromine

(d) Sulphur

Solution:

(b)

Question 35

Which of the following can undergo a chemical reaction?

(a) $M g S O_{4} + F e$

(b $Z n S O_{4} + F e$

(d) $C u S O_{4} + F e$

Solution:

(d)

Question 36

Which one of the following figures correctly describes the process of electrolytic refining?

Solution:

(c)

Question 37

Iqbal treated a lustrous, divalent element M with sodium hydroxide. He observed the formation of bubbles in reaction mixture. He made the same observations when this element was treated with hydrochloric acid. Suggest how he can identify the produced gas? Write chemical equations for both the reactions.

Solution:

The produced gas can be identified by bringing a burning candle near the mouth of the reaction vessel. The gas burns with a pop sound. Hence, it is hydrogen.

$\begin{array}{l} M + 2 N a O H \to N a_{2} M O_{2} + H_{2} \\ M + 2 H C l \to M C l_{2} + H_{2} \end{array}$

Question 38

During extraction of metals, electrolytic refining is used to obtain pure metals.

(a) Which material will be used as anode and cathode for refining of silver metal by this process?

(b) Suggest a suitable electrolyte also.

Solution:

(a) Impure silver will be used as anode whereas pure silver will be used as cathode.

(b) Silver salt, such as $A g N O_{3}$ can be used as the electrolyte.

Question 39

Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them?

Solution:

Compared to the metal sulphides and carbonates, it is easier to obtain the metal from its oxide. Hence, in the process of extraction of metal, the metal sulphides and carbonates should be converted to metal oxides.

Question 40

Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), treated with $H N O_{3}$ , hydrogen is not liberated, why?

Solution:

It is because $H N O_{3}$ is a strong oxidising agent. Hence, it oxidises the hydrogen

( $H_{2}$ ) and produces $H_{2} O$ .

Question 41

Compound X and aluminium are used to join railway tracks.

(a) Identify the compound X

(b) Name the reaction

Solution:

(a) $X — F e_{2} O_{3}$

(b)Thermite reaction

Question 42

When a metal X is treated with cold water, it gives a basic salt Y with molecular formula $X O H (M o l e c u l a r m a s s = 40)$ and liberates a gas Z which easily catches fire. Identify X, Y and Z and also write the reaction involved.

Solution:

$\begin{array}{l} X — N a \\ Y — N a O H \\ Z — H_{2} \end{array}$

$Y — N a O H$

$Z — H_{2}$

Reaction involved

. $2 N a + 2 H_{2} O \to 2 N a O H + H_{2} + H e a t e n e r g y$ .

Question 43

A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance, whereas Z is a good conductor of electricity. Identify X, Y and Z.

Solution:

X $—$ Carbon

Y $—$ Diamond

Z $—$ Graphite

Question 44

The following reaction takes place when aluminium powder is heated with $M n O_{2}$

$3 {MnO}_{2} (s) +4 Al (s) \to 3 Mn (l) +2 {Al}_{2} O_{3} (l) +Heat$

(a) Is aluminium getting reduced?

(b) Is $M n O_{2}$ getting oxidised?

Solution:

(a) No. In the given reaction, oxygen is added to aluminium. Therefore, aluminium is getting oxidized.

(b) No. In the given reaction, manganese loses oxygen. Therefore, manganese is reduced, not oxidised.

Question 45

What are the constituents of solder alloy? Which property of solder makes it suitable for welding electrical wires?

Solution:

The constituents of solder alloy are lead and tin. The property of solder that makes it suitable for welding electrical wires is its low melting point.

Question 46

A metal A, which is used in thermite process, when heated with oxygen gives an oxide B, which is amphoteric in nature. Identify A and B. Write down the reactions of oxide B with $H C l$ and $N a O H$ .

Solution:

$\begin{array}{l} A — A l \\ B — A l_{2} O_{3} \\ A l_{2} O_{3} + 6 H C l \to 2 A l C l_{3} + 3 H_{2} O \\ A l_{2} O_{3} + 2 N a O H \to 2 N a A l O_{2} + H_{2} O \end{array}$

Question 47

A metal that exists as a liquid at room temperature is obtained by heating its sulphide in the presence of air. Identify the metal and its ore and give the reaction involved.

Solution:

The metal is mercury. It is liquid at room temperature. It can be obtained by heating its ore, cinnabar (HgS) in air to convert it into mercury oxide. The oxide is then reduced to mercury by further heating.

The reactions are as follows:

$\begin{array}{l} 2 H g S + 3 O_{2} \overset{H e a t}{\to} 2 H g O + 2 S O_{2} \\ 2 H g O \overset{H e a t}{\to} 2 H g + O_{2} \end{array}$

Question 48

Give the formulae of the stable binary compounds that would be formed by the combination of following pairs of elements.

(a) $M g a n d N_{2}$

(b) $L i a n d O_{2}$

(d) $K a n d O_{2}$

Solution:

(a) $M g_{3} N_{2}$

(b) $L i_{2} O$

(d) $K_{2} O$

Question 49

What happens when:

(a) $Z n C O_{3}$ is heated in the absence of oxygen?

(b) A mixture of $C u_{2} O a n d C u_{2} S$ is heated?

Solution:

(a) When $Z n C O_{3}$ is heated in the absence of oxygen, it undergoes calcination.

$Z n C O_{3} \overset{H e a t}{\to} Z n O + C O_{2}$

(b) When a mixture of $C u_{2} O$ and $C u_{2} S$ is heated, it undergoes auto reduction forming copper and sulphur dioxide.

$2 C u_{2} O + C u_{2} S \overset{H e a t}{\to} 6 C u + S O_{2}$

Question 50

A non-metal A is an important constituent of our food and forms two oxides B and C. Oxide B is toxic whereas C causes global warming

(a) Identify A, B and C

(b) To which Group of Periodic Table does A belong?

Solution:

(a) A is carbon, B is carbon monoxide and C is carbon dioxide.

(b) A belongs to Group $-$ 14 of the periodic table.

Question 51

Give two examples each of the metals that are good conductors and poor conductors of heat respectively.

Solution:

(a) The metals which are good conductors of heat and electricity are silver (Ag) and copper (Cu).

(b) The metals which are poor conductors of heat and electricity are lead (Pb) and mercury (Hg).

Question 52

Name one metal and one non-metal that exist in liquid state at room temperature. Also, name two metals having melting point less than $310 K (37 ° C)$ .

Solution:

Metal $-$ mercury (Hg)

Non-metal $-$ bromine (Br)

Two metals with melting point less than 310 K are caesium (Cs) and gallium (Ga)

Question 53

An element A reacts with water to form a compound B which is used in white washing. The compound B on heating forms an oxide C which on treatment with water gives back B. Identify A, Band C and give the reactions involved.

Solution:

$\begin{array}{l} A — C a \\ B — C a {(O H)}_{2} \\ C — C a O \\ C a (s) + 2 H_{2} O \to C a {(O H)}_{2} (a q) + H_{2} (g) \\ C a {(O H)}_{2} \overset{H e a t}{\to} C a O + H_{2} O \end{array}$

Question 54

An alkali metal A gives a compound B (molecular mass = 40) on reacting with water. The compound B gives a soluble compound C on treatment with aluminium oxide. Identify A, B and C and give the reaction involved.

Solution:

$\begin{array}{l} A — N a \\ B — N a O H \\ C — N a A l O_{2} \end{array}$

Reactions involved

$\begin{array}{l} 2 N a + 2 H_{2} O \to 2 N a O H + H_{2} \\ A l_{2} O_{3} + 2 N a O H \to 2 N a A l O_{2} + H_{2} O \end{array}$

Question 55

Give the reaction involved during extraction of zinc from its ore by

(a) Roasting of zinc ore

(b) Calcination of zinc ore

Solution:

(a) $2 Z n S (s) + 3 O_{2} \overset{H e a t}{\to} 2 Z n O (s) + 2 S O_{2} (g)$

(b) $Z n C O_{3} (s) \overset{H e a t}{\to} Z n O (s) + C O_{2} (g)$

Question 56

A metal M does not liberate hydrogen from acids but reacts with oxygen to give a black colour product. Identify M and black coloured product and also explain the reaction of M with oxygen.

Solution:

The metal M is copper (Cu) which is less reactive and does not liberate hydrogen from acids.

Copper reacts with oxygen and forms a black coloured product, copper(II) oxide (CuO).

Reaction involved: $2 C u + O_{2} \to 2 C u O$

Question 57

An element forms an oxide $A_{2} O_{3}$ which is acidic in nature. Identify A as a metal or non-metal.

Solution:

Since the oxide of the element is acidic in nature, A is a non-metal.

Question 58

A solution of $C u S O_{4}$ was kept in an iron pot. After few days, the iron pot was found to have a number of holes in it. Explain the reason in terms of reactivity. Write the equation of the reaction involved.

Solution:

Since iron ( $F e$ )is more reactive than copper ( $C u$ ), it displaces copper from copper sulphate solution ( $C u S O_{4}$ ) and forms iron sulphate ( $F e S O_{4}$ ). This reaction results in the formation of holes in the iron pot.

The equation of the reaction is as follows:

$F e + C u S O_{4} \to F e S O_{4} + C u$

Question 59

A non-metal A which is the largest constituent of air, when heated with $H_{2}$ in 1:3 ratio in the presence of catalyst ( $F e$ ) gives a gas B. On heating with $O_{2}$ _, it gives an oxide C. If this oxide is passed into water in the presence of air it gives an acid D which acts as a strong oxidising agent.

(a) Identify A, B, C and D

(b) To which group of periodic table does this non-metal belong?

Solution:

(a) $A — N_{2}$

$B — N H_{3}$

$C — N O$

$D — H N O_{3}$

(b) Element A belongs to the Group $-$ 15 of the periodic table

Question 60

Give the steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores.

Solution:

Question 61

Explain the following:

(a) Reactivity of Al decreases if it is dipped in $H N O_{3}$

(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 well as in molten state

(d) Iron articles are galvanised.

(e) Metals like Na, K, Ca and Mg are never found in their free state in nature.

Solution:

a) Due to the formation of an oxide layer i.e., $A l_{2} O_{3}$ , the reactivity of Al decreases.

(b) Compared to carbon (C), sodium (Na) and magnesium (Mg) are more reactive metals. Hence, carbon cannot reduce the oxides of Na or Mg.

(c) Due to its rigid structure, the movement of ions is not possible in solid NaCl. Hence it is not a conductor of electricity in the solid state. But in an aqueous solution or in molten state, the ions can move freely. Hence, it conducts electricity.

(d) Iron articles are galvanised to protect them from corrosion.

(e) Na, K, Ca and Mg are highly reactive. Hence, they are never found in their free states in nature.

Question 62

(i) Given below are the steps for extraction of copper from its ore. Write the reaction involved.

(a) Roasting of copper(1) sulphide

(b) Reduction of copper(1) oxide with copper(1) sulphide.

(ii) Draw a neat and well labelled diagram for electrolytic refining of copper

Solution:

(i)

(a) Roasting of sulphide ore:

$2 C u_{2} S (s) + 3 O_{2} (s) \overset{H e a t}{\to} 2 C u_{2} O (s) + 2 S O_{2} (g)$

(b) $2 C u_{2} O + C u_{2} S \overset{H e a t}{\to} 6 C u (s) + S O_{2} (g)$

At cathode: $C u^{2 +} (a q) + 2 e^{-} \to C u (s)$

At anode: $C u (s) \to C u^{2 +} (a q) + 2 e^{-}$

(ii) Diagram for electrolytic refining of copper:

Question 63

Of the three metals X, Y and Z. X reacts with cold water, Y with hot water and Z with steam only. Identify X, Y and Z and also arrange them in order of increasing reactivity.

Solution:

· X is a metal alkali. It can be either sodium or potassium.

· Y is an alkaline metal. It can be either magnesium or calcium.

· The metal which reacts with steam only is iron.

The increasing reactivity series of the metals are $N a > M g > F e$ .

Question 64

An element A burns with golden flame in air. It reacts with another element B, atomic number 17 to give a product C. An aqueous solution of product C on electrolysis gives a compound D and liberates hydrogen. Identify A, B, C and D. Also, write down the equations for the reactions involved.

Solution:

$\begin{array}{l} A=Na \\ B = C l_{2} \\ C = N a C l \\ D = N a O H \end{array}$

Equations

. $\begin{array}{l} 2 N a + C l_{2} \to 2 N a C l \\ 2 N a C l (a q) + 2 H_{2} O (l) \to 2 N a O H (a q) + C l_{2} (g) + H_{2} (g) \end{array}$ .

Question 65

Two ores A and B were taken. On heating, ore A gives $C O_{2}$ whereas, ore B gives $S O_{2}$ . What steps will you take to convert them into metals?

Solution:

On heating, ore A gives $C O_{2}$ and ore B gives $S O_{2}$ . Therefore, the ores are $M C O_{3}$ and MS.

Steps to convert A into a metal:

$M C O_{3} \overset{C a l c i n a t i o n}{\to} M O + C O_{2}$

$M O + C \overset{Reduction}{\to} M + C O$

Steps to convert B into a metal:

$\begin{array}{l} 2 M S + 3 O_{2} \overset{R o a s t i n g}{\to} 2 M O + 2 S O_{2} \\ M O + C \to M + C O \end{array}$