Mix Examples - Metals and Non-metals Questions in English

(A) Bayer's process is used for the purification of bauxite ore to obtain pure alumina $(Al_2O_3)$.
In this process,the bauxite ore is treated with a concentrated solution of sodium hydroxide $(NaOH)$ at high temperature and pressure.
The impurities like silica,iron oxide,and titanium oxide are removed during the process.
The final alumina obtained after calcination is highly pure,typically containing about $99.5\%$ pure $Al_2O_3$.
Therefore,the impurity remaining in the alumina is approximately $100\% - 99.5\% = 0.5\%$.

(A) The chemical reaction for the hydrolysis of sodium aluminate $(NaAlO_2)$ when excess water is added is as follows:
$NaAlO_2 + 2H_2O \rightarrow NaOH + Al(OH)_3 \downarrow$
In this reaction,sodium aluminate reacts with water to produce sodium hydroxide $(NaOH)$ and aluminium hydroxide $(Al(OH)_3)$.
The aluminium hydroxide $(Al(OH)_3)$ formed is a white gelatinous precipitate.

(B) The extraction of aluminium from pure alumina $(Al_2O_3)$ is carried out by the electrolytic reduction process known as the Hall-Heroult process.
In this process,pure alumina is dissolved in molten cryolite $(Na_3AlF_6)$,which lowers the melting point of the mixture and increases its electrical conductivity.
Electrolysis is then performed in a steel tank lined with carbon,where aluminium is deposited at the cathode.

(C) Alumina $(Al_2O_3)$ is a very stable oxide of aluminum.
It has a very high melting point due to the strong ionic bonds between aluminum and oxygen atoms in its crystal lattice.
The melting point of pure alumina is approximately $2348\;K$ $(2075\;^{\circ}C)$.
Therefore,option $C$ is the correct answer.

(D) Cryolite is a rare mineral with the chemical composition $Na_{3}AlF_{6}$.
It is chemically known as sodium hexafluoroaluminate.
It is primarily used in the electrolytic process of extracting aluminium from alumina $(Al_{2}O_{3})$ to lower the melting point of the mixture and increase its electrical conductivity.

(B) In the $Hall-Heroult$ process,pure alumina $(Al_2O_3)$ has a very high melting point and is a poor conductor of electricity.
To overcome these issues,cryolite $(Na_3AlF_6)$ and fluorspar $(CaF_2)$ are added to the alumina.
These substances lower the melting point of the mixture to approximately $1240 \ K$ and increase its electrical conductivity,facilitating the electrolytic reduction of aluminum.

(C) The most abundant metal in the Earth's crust is $Aluminium$ $(Al)$,which accounts for approximately $8.1\%$ of the crust by weight.
The second most abundant metal in the Earth's crust is $Iron$ $(Fe)$,which accounts for approximately $5.0\%$ of the crust by weight.
Therefore,$Iron$ is the second most abundant metal found on Earth.

(A) The extraction of iron from its ore (mainly hematite, $Fe_2O_3$) is carried out in a $Blast$ furnace.
In this process, iron ore, coke, and limestone are fed into the top of the furnace, while hot air is blasted into the bottom.
The coke acts as a fuel and a reducing agent, converting iron oxides into molten iron.

(B) In a blast furnace, the primary ore used for the extraction of iron is $Hematite$ $(Fe_2O_3)$.
During the process, the ore is reduced by carbon monoxide $(CO)$ at high temperatures to produce molten iron.
The chemical reaction is: $Fe_2O_3 + 3CO \rightarrow 2Fe + 3CO_2$.

(A) In the blast furnace,limestone $(CaCO_3)$ is added as a flux. It decomposes to form calcium oxide $(CaO)$.
$CaCO_3 \rightarrow CaO + CO_2$
The calcium oxide $(CaO)$ reacts with the silica $(SiO_2)$ impurity present in the ore to form molten calcium silicate $(CaSiO_3)$,which is known as slag.
$CaO + SiO_2 \rightarrow CaSiO_3$ (Slag)
Therefore,the correct answer is calcium silicate.

(C) In the blast furnace,iron oxides are reduced by carbon monoxide $(CO)$ at different temperature zones.
$1$. At lower temperatures $(500-800 \ K)$: $3Fe_{2}O_{3} + CO \longrightarrow 2Fe_{3}O_{4} + CO_{2}$ and $Fe_{3}O_{4} + CO \longrightarrow 3FeO + CO_{2}$.
$2$. At higher temperatures $(> 1000 \ K)$: $FeO + CO \longrightarrow Fe + CO_{2}$.
Option $C$ is incorrect because $Fe_{3}O_{4}$ is being reduced to $Fe_{2}O_{3}$ (an oxidation process) and it produces solid carbon,which does not occur in this reduction sequence.

(D) The reactivity series of metals lists metals in descending order of their reactivity.
According to the reactivity series,the order of reactivity for the given metals is $Mg > Zn > Fe > Au$.
$Mg$ (Magnesium) is highly reactive,while $Au$ (Gold) is a noble metal and is the least reactive among the options provided.
Therefore,$Au$ is the correct answer.

(B) The reactivity of metals is determined by their position in the reactivity series.
According to the reactivity series,the order of reactivity for the given metals is $K > Na > Mg > Zn$.
Potassium $(K)$ is at the top of the reactivity series among the options provided,making it the most reactive metal.
Therefore,the correct option is $B$.

(C) The ability of a metal to displace another metal from its salt solution depends on its position in the reactivity series.
$A$ more reactive metal can displace a less reactive metal from its salt solution.
According to the reactivity series,the order of reactivity is: $Mg > Zn > Fe > Cu > Ag$.
Since $Zn$ is more reactive than $Fe$,$Cu$,and $Ag$,it can displace them from their respective salt solutions.
However,$Zn$ is less reactive than $Mg$. Therefore,$Zn$ cannot displace $Mg$ from $MgSO_{4}$ solution.

(A) The ability of a metal to displace another metal from its salt solution depends on its reactivity series position.
Copper $(Cu)$ is less reactive than Zinc $(Zn)$,Magnesium $(Mg)$,and Aluminum $(Al)$.
However,Copper $(Cu)$ is more reactive than Silver $(Ag)$.
According to the reactivity series,a more reactive metal displaces a less reactive metal from its salt solution.
Therefore,$Cu$ can displace $Ag$ from its solution $(AgNO_{3})$,but it cannot displace $Zn$,$Mg$,or $Al$ from their respective salt solutions.

(D) The reactivity series of metals is a list of metals arranged in the order of their decreasing chemical reactivity.
Based on the standard reactivity series: $K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au$.
Evaluating the options:
Option $A$: $Ca > Mg > Ag > Fe$ is incorrect because $Fe > Ag$.
Option $B$: $Zn > Al > Cu > Au$ is incorrect because $Al > Zn$.
Option $C$: $Na > Al > Mg > Cu$ is incorrect because $Mg > Al$.
Option $D$: $Mg > Al > Fe > Cu$ is correct as per the reactivity series where $Mg$ is more reactive than $Al$,$Al$ is more reactive than $Fe$,and $Fe$ is more reactive than $Cu$.

(B) The reactivity series of metals in decreasing order is: $K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au$.
Checking the options:
$A$: $K > Ca > Mg > Zn$ is correct.
$B$: $Na > Al > Mg > Ca$ is incorrect because $Ca$ is more reactive than $Mg$ and $Al$. The correct order should be $Na > Ca > Mg > Al$.
$C$: $Na > Al > Fe > Cu$ is correct.
$D$: $Ca > Zn > Cu > Ag$ is correct.
Therefore,the incorrect order is $B$.

(B) The reactivity series of metals is a list of metals arranged in the order of their decreasing chemical reactivity.
According to the reactivity series, the order of reactivity for the given metals is: $Potassium (K) > Sodium (Na) > Calcium (Ca) > Magnesium (Mg) > Aluminium (Al) > Zinc (Zn) > Iron (Fe) > Lead (Pb) > Hydrogen (H) > Copper (Cu) > Mercury (Hg) > Silver (Ag) > Gold (Au)$.
Comparing the given metals: $Magnesium (Mg)$ is more reactive than $Aluminium (Al)$, $Aluminium (Al)$ is more reactive than $Zinc (Zn)$, and $Zinc (Zn)$ is more reactive than $Iron (Fe)$.
Therefore, the correct order is $Mg > Al > Zn > Fe$.

(A) The reactivity series of metals lists metals in decreasing order of their reactivity.
According to the reactivity series,the order is: $K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au$.
From the given options,Calcium $(Ca)$ is placed above Magnesium $(Mg)$ in the reactivity series,which means it is more reactive than Magnesium.
Iron $(Fe)$,Copper $(Cu)$,and Aluminium $(Al)$ are all less reactive than Magnesium $(Mg)$.

(C) The reactivity of a metal is determined by its ability to displace other metals from their salt solutions. This is known as a displacement reaction.
According to the reactivity series,a more reactive metal can displace a less reactive metal from its salt solution.
For example,if a metal $A$ displaces metal $B$ from the solution of $B$,then metal $A$ is more reactive than metal $B$.

(D) Most metals are solid at room temperature. However,there are exceptions.
$1$. Mercury $(Hg)$ is a metal that is liquid at room temperature.
$2$. Gallium $(Ga)$ and Caesium $(Cs)$ have very low melting points ($29.76 \ ^\circ C$ and $28.44 \ ^\circ C$ respectively),which means they can melt in the palm of a human hand.
Among the given options,Gallium is the metal that exists in a liquid state near room temperature.

(B) Most metals are hard,but alkali metals like $Sodium$ $(Na)$ and $Potassium$ $(K)$ are exceptions.
These metals have low density and low melting points.
Due to their weak metallic bonding,they are soft enough to be cut easily with a knife.

(C) Density is defined as mass per unit volume $(d = m/V)$.
Comparing the densities of the given metals:
$1$. Lead $(Pb)$: $\approx 11.34 \ g/cm^3$
$2$. Tin $(Sn)$: $\approx 7.31 \ g/cm^3$
$3$. Aluminium $(Al)$: $\approx 2.70 \ g/cm^3$
$4$. Mercury $(Hg)$: $\approx 13.53 \ g/cm^3$
Among the given options,Aluminium has the lowest density,making it the lightest metal relative to its volume.

(D) Metals are generally good conductors of heat and electricity. However,$Lead$ $(Pb)$ and $Mercury$ $(Hg)$ are known to be comparatively poor conductors of heat and electricity among metals. Therefore,among the given options,$Lead$ is the correct answer.

(C) Aluminium oxide $(Al_2O_3)$ is an amphoteric oxide.
An amphoteric oxide is a substance that can react with both acids and bases to produce salt and water.
For example,it reacts with hydrochloric acid $(HCl)$ to form aluminium chloride $(AlCl_3)$ and water $(H_2O)$.
It also reacts with sodium hydroxide $(NaOH)$ to form sodium aluminate $(NaAlO_2)$ and water $(H_2O)$.

(A) Metal oxides are generally basic in nature. Most metal oxides are insoluble in water,but some dissolve in water to form alkalis.
Among the given options,$Na_{2}O$ (Sodium oxide) is a highly reactive metal oxide that reacts with water to form a strong alkali,Sodium hydroxide $(NaOH)$.
The reaction is: $Na_{2}O(s) + H_{2}O(l) \rightarrow 2NaOH(aq)$.
$Al_{2}O_{3}$ and $ZnO$ are amphoteric oxides,and $Fe_{2}O_{3}$ is insoluble in water.

(B) Sodium $(Na)$ is a highly reactive metal. It reacts vigorously with oxygen and moisture present in the air,which can lead to fire. To prevent this reaction,sodium is stored immersed in kerosene oil,as it does not react with kerosene.

(A) Magnesium $(Mg)$ is a highly reactive metal. When a magnesium ribbon is heated in the presence of oxygen,it undergoes a combustion reaction to form magnesium oxide $(MgO)$. This reaction is highly exothermic and releases a significant amount of heat and light. The light produced is characteristically intense and dazzling white,which is why magnesium is often used in fireworks and flash photography.

(C) The reactivity of metals with water depends on their position in the reactivity series.
Alkali metals like $Potassium$ $(K)$ and $Sodium$ $(Na)$ are highly reactive.
$Potassium$ reacts violently with cold water to form $Potassium$ hydroxide $(KOH)$ and hydrogen gas $(H_2)$, releasing a large amount of heat which causes the hydrogen to catch fire immediately.
The reaction is: $2K(s) + 2H_2O(l) \rightarrow 2KOH(aq) + H_2(g) + \text{Heat}$.

(D) Metals react with water to form metal oxides and hydrogen gas.
$1$. Calcium reacts with cold water.
$2$. Magnesium does not react with cold water but reacts with hot water.
$3$. Iron $(Fe)$ does not react with cold or hot water. However,it reacts with steam to form iron oxide $(Fe_3O_4)$ and hydrogen gas $(H_2)$.
The chemical equation is: $3Fe(s) + 4H_2O(g) \rightarrow Fe_3O_4(s) + 4H_2(g)$.
Therefore,Iron is the correct answer.

(B) The reactivity of metals with water depends on their position in the reactivity series.
$1$. Magnesium $(Mg)$ reacts with hot water.
$2$. Aluminium $(Al)$ and Iron $(Fe)$ react with steam.
$3$. Gold $(Au)$ is a noble metal located at the bottom of the reactivity series. It is highly unreactive and does not react with water,steam,or even acids under normal conditions.

(C) The property of a metal by which it can be beaten into thin sheets is known as malleability.
Gold and silver are the most malleable metals.
Silver is commonly used to make very thin foils,often used for decorative purposes in food items (like silver leaf or 'vark').
Therefore,silver is the correct answer.

(B) The number of electrons that an atom of an element loses,gains,or shares to complete its octet is known as its valency. In the case of metals,they lose electrons from their outermost shell to form positive ions (cations). The number of electrons lost by a metal atom to achieve a stable electronic configuration is defined as its valency.

(A) Potassium $(K)$ is a highly reactive alkali metal. It reacts vigorously with oxygen in the air to form potassium oxide $(K_2O)$ and potassium peroxide $(K_2O_2)$. Due to this high reactivity,it reacts spontaneously with atmospheric moisture and oxygen,which can cause it to catch fire. Therefore,it is stored under kerosene to prevent contact with air and moisture.

(C) The reactivity of metals with oxygen depends on their position in the reactivity series.
Metals like $Calcium$ $(Ca)$ and $Magnesium$ $(Mg)$ are highly reactive and react with oxygen to form metal oxides even at room temperature or upon heating.
$Copper$ $(Cu)$ reacts with oxygen only at high temperatures to form $Copper(II)$ oxide $(CuO)$.
$Silver$ $(Ag)$ and $Gold$ $(Au)$ are noble metals located at the bottom of the reactivity series.
These metals are very unreactive and do not react with oxygen even at high temperatures,which is why they remain lustrous and do not tarnish easily.

(C) When sodium metal $(Na)$ reacts with water $(H_2O)$,it forms sodium hydroxide $(NaOH)$ and releases hydrogen gas $(H_2)$.
This is a highly exothermic reaction.
The balanced chemical equation is:
$2Na_{(s)} + 2H_2O_{(l)} \longrightarrow 2NaOH_{(aq)} + H_{2(g)}$
Therefore,the correct option is $C$.

(B) Reactive metals such as sodium $(Na)$ and potassium $(K)$ are highly electropositive. When they react with dihydrogen $(H_2)$ at high temperatures,they form ionic or saline hydrides. The general reaction is: $2M(s) + H_2(g) \rightarrow 2MH(s)$,where $M$ represents the metal. For example,$2Na(s) + H_2(g) \rightarrow 2NaH(s)$.

(A) Rust is a hydrated iron$(III)$ oxide,which forms when iron reacts with oxygen and moisture in the air.
Its chemical formula is represented as $Fe_{2}O_{3} \cdot xH_{2}O$,where $x$ represents a variable number of water molecules.

(B) The process of coating iron or steel with a thin layer of zinc to prevent rusting is known as galvanization. Therefore,iron coated with a layer of zinc is called galvanized iron. This protective layer acts as a barrier,preventing the iron from coming into contact with moisture and oxygen,which are necessary for the formation of rust.

(C) Copper carbonate $(CuCO_3)$ is a chemical compound that appears as a green-colored powder or salt. It is commonly found in nature as the mineral malachite. Therefore,the correct color of copper carbonate salt is green.

(D) Stainless steel is an alloy of iron,chromium,and nickel.
It is highly resistant to corrosion and rust,which makes it ideal for the manufacturing of surgical instruments that need to be sterilized frequently.
Unlike ordinary steel,it does not react with water or air easily,ensuring the durability and hygiene of medical tools.

(A) Stainless steel is an alloy primarily composed of iron $(Fe)$,chromium $(Cr)$,and nickel $(Ni)$.
Chromium is added to provide corrosion resistance,while nickel improves the mechanical properties and ductility of the steel.
Carbon is also present in small amounts,but the primary alloying elements that define stainless steel are iron,chromium,and nickel.

(B) An alloy is a homogeneous mixture of two or more metals,or a metal and a non-metal.
$A$. Copper $(Cu)$ is a pure chemical element.
$B$. Brass is an alloy consisting of copper $(Cu)$ and zinc $(Zn)$.
$C$. Chromium $(Cr)$ is a pure chemical element.
$D$. Magnesium $(Mg)$ is a pure chemical element.
Therefore,the correct answer is $B$.

(D) Brass is an alloy primarily composed of copper $(Cu)$ and zinc $(Zn)$.
German silver consists of copper,zinc,and nickel.
Duralumin is an alloy of aluminum,copper,magnesium,and manganese.
Bronze is an alloy of copper and tin $(Sn)$.

(B) An alloy is a homogeneous mixture of two or more metals,or a metal and a non-metal.
$A$. Copper $(Cu)$ is a pure metal.
$B$. Magnalium is an alloy of aluminum $(Al)$ and magnesium $(Mg)$.
$C$. Iron $(Fe)$ is a pure metal.
$D$. Zinc $(Zn)$ is a pure metal.
Therefore,Magnalium is the correct answer.

(D) An alloy is a homogeneous mixture of two or more metals,or a metal and a non-metal.
When one of the metals in an alloy is $Mercury$ $(Hg)$,the resulting alloy is specifically known as an $Amalgam$.
For example,sodium amalgam $(Na-Hg)$ is commonly used in chemical reactions.

(A) Brass is an alloy primarily composed of $Copper$ $(Cu)$ and $Zinc$ $(Zn)$.
It is widely used for its aesthetic appeal,corrosion resistance,and acoustic properties.
Therefore,the correct option is $A$.

(B) An alloy is a homogeneous mixture of two or more metals or a metal and a non-metal.
Bronze is an alloy primarily composed of copper $(Cu)$ and tin $(Sn)$.
Brass is an alloy of copper $(Cu)$ and zinc $(Zn)$.
Steel is an alloy of iron $(Fe)$ and carbon $(C)$.
German silver is an alloy of copper $(Cu)$,zinc $(Zn)$,and nickel $(Ni)$.
Therefore,the correct option is $B$.

(D) Magnalium is an alloy of aluminum and magnesium. It typically contains $90-95\%$ aluminum and $5-10\%$ magnesium. It is known for its high strength,low density,and corrosion resistance,making it useful in aerospace and automotive applications.

(C) Bronze is an alloy primarily composed of copper $(Cu)$ and tin $(Sn)$.
It is highly resistant to corrosion and possesses excellent casting properties,making it the ideal material for creating statues,medals,and various artistic artifacts.