Mix Examples - Metals and Non-metals Questions in English

(N/A) Good conductors of heat: Silver $(Ag)$ and Copper $(Cu)$.
$(b)$ Poor conductors of heat: Lead $(Pb)$ and Mercury $(Hg)$.

(N/A) The metal that exists in a liquid state at room temperature is Mercury $(Hg)$.
The non-metal that exists in a liquid state at room temperature is Bromine $(Br)$.
Two metals that have a melting point less than $310\ K$ $(37\ ^\circ C)$ are Cesium $(Cs)$ and Gallium $(Ga)$.

(A) The element $A$ is Calcium $(Ca)$.
When $Ca$ reacts with water,it forms Calcium hydroxide $(Ca(OH)_2)$,which is compound $B$ and is used for white washing.
Reaction: $Ca(s) + 2H_2O(l) \rightarrow Ca(OH)_2(aq) + H_2(g)$
When $Ca(OH)_2$ is heated,it decomposes to form Calcium oxide $(CaO)$,which is oxide $C$.
Reaction: $Ca(OH)_2(s) \xrightarrow{\text{Heat}} CaO(s) + H_2O(g)$
When $CaO$ is treated with water,it gives back $Ca(OH)_2$.
Reaction: $CaO(s) + H_2O(l) \rightarrow Ca(OH)_2(aq)$
Therefore,$A = Ca$,$B = Ca(OH)_2$,and $C = CaO$.

(A) The alkali metal $A$ is Sodium $(Na)$.
When $Na$ reacts with water,it forms Sodium hydroxide $(NaOH)$ as compound $B$.
The molecular mass of $NaOH = 23 + 16 + 1 = 40$.
When $NaOH$ $(B)$ reacts with aluminium oxide $(Al_{2}O_{3})$,it forms Sodium aluminate $(NaAlO_{2})$ as compound $C$,which is soluble in water.
The reactions are:
$2Na + 2H_{2}O \rightarrow 2NaOH + H_{2}$
$Al_{2}O_{3} + 2NaOH \rightarrow 2NaAlO_{2} + H_{2}O$

(N/A) Roasting is the process of heating a sulphide ore in the presence of excess air. The reaction for zinc sulphide $(ZnS)$ is:
$2ZnS(s) + 3O_2(g) \xrightarrow{\text{Heat}} 2ZnO(s) + 2SO_2(g)$
$(b)$ Calcination is the process of heating a carbonate ore in the absence or limited supply of air. The reaction for zinc carbonate $(ZnCO_3)$ is:
$ZnCO_3(s) \xrightarrow{\text{Heat}} ZnO(s) + CO_2(g)$

(N/A) The metal $M$ is Copper $(Cu)$.
Copper is less reactive than hydrogen in the reactivity series,so it does not displace hydrogen from dilute acids.
When copper is heated in the presence of oxygen,it undergoes oxidation to form Copper$(II)$ oxide $(CuO)$,which is a black-coloured substance.
The chemical reaction is:
$2Cu(s) + O_2(g) \rightarrow 2CuO(s)$ (Black product)

(B) Non-metals typically form acidic oxides when they react with oxygen. Since the oxide $A_{2}O_{3}$ is acidic in nature,the element $A$ must be a non-metal.

(N/A) $Fe$ is more reactive than $Cu$. According to the reactivity series,$Fe$ can displace $Cu$ from its salt solution.
When $CuSO_{4}$ solution is kept in an iron pot,$Fe$ reacts with $CuSO_{4}$ to form $FeSO_{4}$ and $Cu$ is deposited.
This reaction causes the iron pot to corrode,leading to the formation of holes.
The chemical equation for this displacement reaction is:
$Fe(s) + CuSO_{4}(aq) \rightarrow FeSO_{4}(aq) + Cu(s)$

$(A) A = N_2$ (Nitrogen), $B = NH_3$ (Ammonia), $C = NO$ (Nitric oxide), $D = HNO_3$ (Nitric acid).
Step $1$: Nitrogen $(N_2)$ is the most abundant gas in the atmosphere.
Step $2$: Haber's process: $N_2 + 3H_2 \xrightarrow{Fe} 2NH_3$ (Gas $B$).
Step $3$: Catalytic oxidation: $N_2 + O_2 \rightarrow 2NO$ (Oxide $C$).
Step $4$: Formation of acid: $4NO + 3O_2 + 2H_2O \rightarrow 4HNO_3$ (Acid $D$).
$(b)$ Nitrogen $(N_2)$ belongs to Group $15$ of the Periodic Table.

(N/A) For metals of low reactivity:
Sulphide ore $\xrightarrow{\text{Roasting}}$ Metal $\xrightarrow{\text{Refining}}$ Pure metal
For metals of medium reactivity:
Sulphide ore $\xrightarrow{\text{Roasting}}$ Metal oxide $\xrightarrow{\text{Reduction}}$ Metal $\xrightarrow{\text{Refining}}$ Pure metal
$1$. Roasting: The sulphide ore is heated strongly in the presence of excess air to convert it into metal oxide (for medium reactivity) or directly into metal (for low reactivity).
$2$. Reduction: The metal oxide obtained is reduced to metal using a suitable reducing agent like carbon.
$3$. Refining: The crude metal obtained is purified through various methods like electrolytic refining.

(N/A) When $Al$ is dipped in $HNO_3$,a thin,protective,and non-reactive layer of aluminum oxide $(Al_2O_3)$ forms on its surface. This layer prevents further reaction of the metal with the acid,thereby decreasing its reactivity.
$(b)$ $Na$ and $Mg$ are highly reactive metals that have a much stronger affinity for oxygen than carbon does. Therefore,carbon cannot displace oxygen from $Na_2O$ or $MgO$ to reduce them to their respective metals.

(A) In solid $NaCl$,the movement of ions is not possible due to its rigid structure. However,in aqueous solution or molten state,the electrostatic forces of attraction are overcome,allowing the ions to move freely and conduct electricity.
$(b)$ Iron articles are galvanised to protect them from corrosion (rusting). Galvanisation involves coating iron with a thin layer of zinc,which is more reactive than iron and prevents the iron from coming into contact with oxygen and moisture.
$(c)$ Metals like $Na, K, Ca$ and $Mg$ are highly reactive. They readily react with other elements such as oxygen,sulfur,and carbon present in the environment to form compounds like oxides,sulfides,or carbonates,and therefore are never found in their free elemental state in nature.

(N/A) $(i)$ $(a)$ Roasting of sulphide ore:
$2Cu_2S(s) + 3O_2(g) \xrightarrow{\Delta} 2Cu_2O(s) + 2SO_2(g)$
$(b)$ Reduction of copper $(I)$ oxide:
$2Cu_2O(s) + Cu_2S(s) \xrightarrow{\Delta} 6Cu(s) + SO_2(g)$
This reaction is known as auto-reduction.
$(c)$ Reaction for electrolytic refining:
At cathode: $Cu^{2+}(aq) + 2e^- \rightarrow Cu(s)$
At anode: $Cu(s) \rightarrow Cu^{2+}(aq) + 2e^-$
$(ii)$ The diagram for the electrolytic refining of copper shows an electrolytic tank containing acidified copper sulphate solution,an impure copper anode,a pure copper cathode,and the collection of anode mud at the bottom.

(A) $X$ is an alkali metal,such as $Na$ or $K$,which is highly reactive and reacts with cold water.
$Y$ is an alkaline earth metal,such as $Mg$ or $Ca$,which reacts with hot water.
$Z$ is a metal like $Fe$ (iron),which reacts only with steam.
The order of increasing reactivity is $Z < Y < X$,which corresponds to $Fe < Mg < Na$.

(A) $A = Na$ (Sodium),$B = Cl_2$ (Chlorine),$C = NaCl$ (Sodium chloride),$D = NaOH$ (Sodium hydroxide).
$1$. Reaction of $A$ with $B$: $2Na(s) + Cl_2(g) \rightarrow 2NaCl(s)$.
$2$. Electrolysis of aqueous solution of $C$ (Chlor-alkali process): $2NaCl(aq) + 2H_2O(l) \rightarrow 2NaOH(aq) + Cl_2(g) + H_2(g)$.

(N/A) Since ore $A$ releases $CO_2$ upon heating, it is a carbonate ore. Carbonate ores are converted into metal oxides by the process of $Calcination$ (heating in limited supply of air).
$MCO_3 \xrightarrow{Calcination} MO + CO_2$
Then, the metal oxide is reduced to metal using a reducing agent like carbon:
$MO + C \xrightarrow{Reduction} M + CO$
Since ore $B$ releases $SO_2$ upon heating, it is a sulfide ore. Sulfide ores are converted into metal oxides by the process of $Roasting$ (heating in excess supply of air).
$2MS + 3O_2 \xrightarrow{Roasting} 2MO + 2SO_2$
Then, the metal oxide is reduced to metal using a reducing agent like carbon:
$MO + C \rightarrow M + CO$

(A) Metal oxides that react with both acids and bases to produce salt and water are called Amphoteric oxides. Examples include $Al_2O_3$ and $ZnO$.
$(b)$ Although most non-metals are dull,Iodine is an exception as it possesses a metallic sheen or luster,hence it is described as Lustrous.

(N/A) When steam is passed over hot aluminium,it reacts to form aluminium oxide and hydrogen gas.
The balanced chemical equation for this reaction is:
$2Al(s) + 3H_2O(g) \rightarrow Al_2O_3(s) + 3H_2(g) \uparrow$
In this reaction,aluminium metal reacts with steam (gaseous water) at high temperatures to produce aluminium oxide and hydrogen gas.

(A) When carbon dioxide $(CO_2)$ is dissolved in water under high pressure,it reacts with water to form carbonic acid $(H_2CO_3)$.
The chemical equation for this reaction is:
$CO_2(g) + H_2O(l) \rightarrow H_2CO_3(aq)$

(N/A) Electrical wires are typically made of copper,which is an excellent conductor of electricity. However,copper is reactive and can undergo corrosion when exposed to moist air containing carbon dioxide,leading to the formation of a green layer of copper carbonate. Furthermore,copper is a metal and poses a risk of electric shock if touched directly. Plastic acts as an insulator,preventing electric shocks and protecting the metal wire from environmental corrosion.

(N/A) Brass is an alloy composed of Copper $(Cu)$ and Zinc $(Zn)$.
Bronze is an alloy composed of Copper $(Cu)$ and Tin $(Sn)$.

(B) Rust is chemically known as hydrated iron$(III)$ oxide.
When iron reacts with oxygen and moisture in the air,it forms a reddish-brown substance called rust.
The general chemical formula for rust is $Fe_2O_3 \cdot xH_2O$,where $x$ represents a variable number of water molecules.

(N/A) The alloy used for electrical fuses is $Solder$. Its constituents are $Lead$ $(Pb)$ and $Tin$ $(Sn)$.

(N/A) The metal that exists in a liquid state at room temperature is $Mercury$ $(Hg)$.
The non-metal that exists in a liquid state at room temperature is $Bromine$ $(Br_2)$.

(N/A) Generally,metals do not evolve $H_{2}$ gas when reacting with dilute $HNO_{3}$ because it is a strong oxidizing agent that oxidizes the produced $H_{2}$ to water. However,magnesium $(Mg)$ and manganese $(Mn)$ are exceptions that react with very dilute $HNO_{3}$ to evolve $H_{2}$ gas.

(N/A) Highly reactive metals (such as $Na, Mg, Ca, Al$) have a much stronger affinity for oxygen than carbon does. Because their bond with oxygen is significantly more stable,carbon is unable to displace the metal from its oxide. Therefore,these metals are extracted from their ores by electrolytic reduction rather than carbon reduction.

(N/A) When sodium $(Na)$ is exposed to air,it reacts with moisture $(H_2O)$ present in the air to form sodium hydroxide $(NaOH)$ and releases hydrogen gas $(H_2)$.
The chemical equation for this reaction is:
$2Na(s) + 2H_2O(l) \longrightarrow 2NaOH(aq) + H_2(g)$

(B) The extraction of metals from their sulphide and carbonate ores is difficult because these compounds are chemically stable and do not easily release the metal.
However,metal oxides are much easier to reduce to pure metal using reducing agents like carbon or through electrolytic reduction.
Therefore,sulphide ores are first converted into oxides by roasting (heating in the presence of excess air),and carbonate ores are converted into oxides by calcination (heating in the absence or limited supply of air).

(B) $(i)$ Magnesium $(Mg)$ reacts with hot water or steam only when it is in a heated state or boiling,as it forms magnesium hydroxide and hydrogen gas.
$(ii)$ Copper $(Cu)$ is a less reactive metal (placed below hydrogen in the reactivity series) and does not react with water or steam at all.

(IRON) Iron $(Fe)$,aluminium $(Al)$,and zinc $(Zn)$ do not react with either cold or hot water. They react with steam to form metal oxide and hydrogen gas. For example,the reaction of iron with steam is:
$3Fe(s) + 4H_2O(g) \longrightarrow Fe_3O_4(s) + 4H_2(g)$

(N/A) The two metals that have very low melting points are:
$(i)$ Caesium $(Cs)$
$(ii)$ Gallium $(Ga)$
These metals are so sensitive to heat that they can melt in the palm of a human hand.

(N/A) Iodine is a non-metal that exhibits luster (lustrous).
Sodium or Potassium are examples of metals that appear dull (non-lustrous) when exposed to air due to the formation of an oxide layer,or more commonly,metals like Iron in its powdered or oxidized form are considered non-lustrous.

(N/A) When aluminium is heated in air,it reacts with oxygen to form aluminium oxide.
The balanced chemical equation is: $4 Al + 3 O_{2} \rightarrow 2 Al_{2}O_{3}$.
The product formed is aluminium oxide $(Al_{2}O_{3})$.

(C) Ionic compounds consist of ions held together by strong electrostatic forces of attraction in a rigid crystal lattice.
In the solid state,these ions are fixed in their positions and are not free to move.
Since the conduction of electricity requires the movement of charged particles (ions),ionic compounds cannot conduct electricity in the solid state.
They only conduct electricity when molten or dissolved in water,as the ions become free to move in these states.

(N/A) The atomic number of magnesium $(Mg)$ is $12$, and its electronic configuration is $2, 8, 2$. It has $2$ valence electrons.
The atomic number of chlorine $(Cl)$ is $17$, and its electronic configuration is $2, 8, 7$. It has $7$ valence electrons.
To form magnesium chloride $(MgCl_2)$, the magnesium atom loses $2$ electrons to achieve a stable octet configuration, forming a $Mg^{2+}$ ion.
Each of the two chlorine atoms gains $1$ electron from the magnesium atom to complete their octets, forming two $Cl^-$ ions.
The electron dot structure and transfer process are as follows:
$Mg: + 2 \cdot \ddot{Cl}: \rightarrow [Mg^{2+}] [: \ddot{Cl}:^-]_2$

(A) Sodium chloride $(NaCl)$ is an ionic compound consisting of $Na^+$ and $Cl^-$ ions held together by strong electrostatic forces of attraction.
Water is a polar solvent with a high dielectric constant,which helps in overcoming the electrostatic forces of attraction between the ions,allowing $NaCl$ to dissociate and dissolve.
Conversely,kerosene is a non-polar organic solvent.
It lacks the ability to provide the necessary energy to break the strong ionic bonds in $NaCl$,and therefore,$NaCl$ remains insoluble in it.

(N/A) $(i)$ Aluminium does not corrode easily because,upon exposure to air,its surface forms a thin,protective,and non-reactive layer of aluminium oxide $(Al_2O_3)$. This layer prevents further oxidation of the metal.
$(ii)$ Copper vessels develop a green coating in the rainy season because copper reacts with moist carbon dioxide $(CO_2)$ and water vapor in the air to form a mixture of copper carbonate $(CuCO_3)$ and copper hydroxide $(Cu(OH)_2)$,which is green in color.

(IONIC BOND) The bond formed by the transfer of electrons from a metal to a non-metal is an $Ionic$ bond.
The general properties of ionic compounds are:
$(i)$ They are usually crystalline solids due to strong electrostatic forces of attraction.
$(ii)$ They have high melting and boiling points.
$(iii)$ They are generally soluble in water but insoluble in organic solvents like kerosene or petrol.
$(iv)$ They conduct electricity in their molten state or in aqueous solution because the ions become free to move.

(N/A) Metals are sonorous,meaning they produce a ringing sound when struck. Therefore,they are used to make school bells.
$(b)$ Copper is an excellent conductor of electricity with low electrical resistance. Therefore,it is used for making electrical wires.

(N/A) Activity: Take a small amount of the salt solution of metal $P$ in a test tube and add metal $Q$ to it. Since metal $Q$ is more reactive than metal $P$, it will displace metal $P$ from its salt solution.
Chemical equation:
Metal $Q + \text{Salt solution of } P \rightarrow \text{Salt solution of } Q + \text{Metal } P$

(N/A) 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 primary metal and then dissolving the other elements in it in definite proportions.

(A) Sodium and potassium are highly reactive metals.
When kept in the open,they react vigorously with oxygen and moisture present in the atmosphere to form their respective oxides and hydroxides,releasing a large amount of heat.
This heat is sufficient to ignite the metal,causing it to catch fire.
Therefore,to prevent these reactions and accidental fires,they are stored immersed in kerosene oil,as they do not react with it.

(N/A) Nitric acid $(HNO_{3})$ is a strong oxidizing agent. When a metal reacts with it,the hydrogen gas $(H_{2})$ produced is immediately oxidized to water $(H_{2}O)$ by the nitric acid. Simultaneously,the nitric acid itself gets reduced to various nitrogen oxides,such as nitrous oxide $(N_{2}O)$,nitric oxide $(NO)$,or nitrogen dioxide $(NO_{2})$.

(N/A) Iron is galvanised with zinc to protect it from rusting. This is because zinc is more reactive (more electropositive) than iron,so it forms a protective layer that prevents corrosion. Copper is less reactive (less electropositive) than iron. Therefore,iron cannot be galvanised with copper because copper would actually accelerate the corrosion of iron if the coating were damaged.

(N/A)

Roasting	Calcination
$1.$ In this,the ore is heated in the presence of excess air.	$1.$ In this,the ore is heated in the absence or limited supply of air.
$2.$ It is primarily done for sulphide ores.	$2.$ It is primarily done for carbonate ores.
$3.$ $SO_2$ gas is evolved.	$3.$ $CO_2$ gas is evolved.
$4.$ Example: $2ZnS + 3O_2 \xrightarrow{\text{heat}} 2ZnO + 2SO_2$	$4.$ Example: $ZnCO_3 \xrightarrow{\text{heat}} ZnO + CO_2$

(N/A) The primary ore of mercury is $HgS$,known as Cinnabar.
Extraction process:
$1$. Roasting: The ore $HgS$ is first heated in the presence of excess air to convert it into mercuric oxide $(HgO)$.
$2HgS + 3O_2 \xrightarrow{\Delta} 2HgO + 2SO_2$
$2$. Reduction: Mercuric oxide $(HgO)$ is then reduced to metallic mercury $(Hg)$ by further heating,as it is unstable at high temperatures.
$2HgO \xrightarrow{\Delta} 2Hg + O_2$

(N/A) Copper is obtained from copper$(I)$ sulfide $(Cu_{2}S)$ through a process known as self-reduction or auto-reduction by heating it in the presence of air.
First,a portion of the copper$(I)$ sulfide is converted into copper$(I)$ oxide by heating it in air:
$2Cu_{2}S + 3O_{2} \xrightarrow{\Delta} 2Cu_{2}O + 2SO_{2}$
Then,the remaining copper$(I)$ sulfide reacts with the copper$(I)$ oxide formed to produce metallic copper:
$2Cu_{2}O + Cu_{2}S \xrightarrow{\Delta} 6Cu + SO_{2}$

(N/A) $(i)$ Metals contain free electrons that can move throughout the metallic lattice,allowing them to conduct electricity.
$(ii)$ Non-metals are electron acceptors. To displace hydrogen from dilute acids,electrons must be supplied to the $H^+$ ions of the acid. Since non-metals cannot donate electrons,they cannot displace hydrogen.
$(iii)$ Aluminium reacts with oxygen to form a thin,protective layer of aluminium oxide $(Al_2O_3)$ on its surface. This layer is non-reactive and prevents further oxidation of the underlying metal,making it suitable for kitchen utensils.

(N/A) Calcium reacts with water to form calcium hydroxide and hydrogen gas. The hydrogen gas produced during the reaction forms bubbles that stick to the surface of the calcium metal,causing it to float.
$Ca(s) + 2H_2O(l) \to Ca(OH)_2(aq) + H_2(g)$

(A) $(i)$ The molecular formula of $Y$ is $XOH$ and its molecular mass is $40$. The atomic mass of $O$ is $16$ and $H$ is $1$. Thus,$X + 16 + 1 = 40$,which gives $X = 23$. The element with atomic mass $23$ is Sodium $(Na)$.
$(ii)$ When sodium $(Na)$ reacts with cold water,it forms sodium hydroxide $(NaOH)$ and releases hydrogen gas $(H_2)$.
$(iii)$ Hydrogen gas $(H_2)$ is highly flammable and catches fire easily.
$(iv)$ Therefore,$X = Na$,$Y = NaOH$,and $Z = H_2$.