Chemical Properties of Metals Questions in English

(D) Voltaic cell (or simple galvanic cell) consists of two electrodes immersed in an electrolyte.
In this cell,the zinc plate acts as the negative electrode (anode) and the copper plate acts as the positive electrode (cathode).
Therefore,the positive electrode is made of copper.

(A) Voltaic cell (or simple galvanic cell) consists of two different metal electrodes,typically zinc and copper,immersed in an electrolyte solution.
In the original design by Alessandro Volta,the electrolyte used is dilute sulfuric acid $(H_2SO_4)$.
The zinc electrode acts as the anode (negative terminal) and the copper electrode acts as the cathode (positive terminal).

(A) In the process of electroplating,the object to be coated (in this case,the steel spoon) is connected to the negative terminal (cathode) of the battery.
The metal to be deposited (in this case,the copper rod) is connected to the positive terminal (anode) of the battery.
When the current flows,copper ions from the copper rod dissolve into the electrolyte and get deposited on the steel spoon connected to the negative terminal.
Therefore,the copper rod must be connected to the positive terminal.

(A) In the process of electroplating,the object to be coated (in this case,the iron spoon) is connected to the negative terminal (cathode) of the battery. The metal to be deposited (in this case,the chromium rod) is connected to the positive terminal (anode). When the current flows,chromium ions from the rod dissolve into the electrolyte and get deposited on the iron spoon.

(C) Metal oxides are generally basic in nature. When they react with water,they form metal hydroxides,which are basic solutions.
For example,sodium oxide $(Na_2O)$ reacts with water $(H_2O)$ to form sodium hydroxide $(NaOH)$,which is a strong base.
$Na_2O(s) + H_2O(l) \rightarrow 2NaOH(aq)$.

(A) An oxide of a metal is formed when a metal reacts with oxygen.
Calcium $(Ca)$ is a metal,and its reaction with oxygen produces calcium oxide $(CaO)$,which is a metallic oxide.
Carbon $(C)$,sulfur $(S)$,and oxygen $(O)$ are non-metals,so their oxides ($CO_2$,$SO_3$,$SO_2$) are non-metallic oxides.

(D) The reactivity of metals with acids depends on their position in the reactivity series.
Metals that are more reactive than hydrogen can displace hydrogen from acids to form salt and hydrogen gas.
$Ca$,$Mg$,and $Zn$ are more reactive than hydrogen and react with acids to release $H_2$ gas.
$Au$ (Gold) is a noble metal and is placed below hydrogen in the reactivity series.
Therefore,$Au$ does not react with dilute acids to evolve hydrogen gas.

(B) Sodium hydroxide $(NaOH)$ is a strong base. Most metals do not react with bases,but amphoteric metals like Aluminum $(Al)$,Zinc $(Zn)$,and Lead $(Pb)$ react with strong bases to form complex salts and release hydrogen gas $(H_2)$.
For the reaction of Aluminum with sodium hydroxide:
$2Al + 2NaOH + 6H_2O \rightarrow 2Na[Al(OH)_4] + 3H_2 \uparrow$
Here,$Na[Al(OH)_4]$ is sodium tetrahydroxoaluminate (a salt) and $H_2$ is hydrogen gas. Therefore,$Al$ is the correct metal.

(C) When metals react with dilute sulphuric acid or dilute hydrochloric acid,they typically displace hydrogen to form metal salts and release dihydrogen gas $(H_2)$.
However,dilute nitric acid $(HNO_3)$ is a strong oxidizing agent.
When a metal reacts with dilute $HNO_3$,the hydrogen gas produced is immediately oxidized to water $(H_2O)$ by the nitric acid,which itself gets reduced to nitrogen oxides $(N_2O, NO, NO_2)$.
Therefore,dihydrogen gas is not evolved in this reaction under normal conditions.

(D) displacement reaction occurs when a more reactive metal displaces a less reactive metal from its salt solution.
According to the reactivity series of metals,the order of reactivity is $Mg > Al > Fe > Cu > Ag$.
In option $A$,$Cu$ is less reactive than $Na$,so no reaction occurs.
In option $B$,$Al$ is less reactive than $Mg$,so no reaction occurs.
In option $C$,$Ag$ is less reactive than $Fe$,so no reaction occurs.
In option $D$,$Cu$ is more reactive than $Ag$. Therefore,$Cu$ can displace $Ag$ from the $AgNO_3$ solution,resulting in the reaction: $Cu(s) + 2AgNO_3(aq) \rightarrow Cu(NO_3)_2(aq) + 2Ag(s)$.

(D) chemical reaction is possible if a more reactive metal displaces a less reactive metal from its salt solution. According to the reactivity series of metals,the order is $Zn > Fe > Cu$.
$1$. In option $A$,$Zn$ is more reactive than $Cu$,so it displaces $Cu$. This reaction is possible.
$2$. In option $B$,$Zn$ is more reactive than $Fe$,so it displaces $Fe$. This reaction is possible.
$3$. In option $C$,$Fe$ is more reactive than $Cu$,so it displaces $Cu$. This reaction is possible.
$4$. In option $D$,$Cu$ is less reactive than $Fe$. Therefore,$Cu$ cannot displace $Fe$ from $FeSO_4$ solution. This reaction is not possible.

(C) Solder is an alloy that is primarily used for joining metal components,especially in electrical circuits.
It is composed of two main metals: Lead $(Pb)$ and Tin $(Sn)$.
This alloy has a low melting point,which allows it to be melted easily using a soldering iron to create a permanent electrical connection between wires and components.

(A) Noble metals are metals that are resistant to corrosion and oxidation in moist air.
They are found in their native state in the Earth's crust because they are chemically inert or very less reactive.
Examples of noble metals include Gold $(Au)$,Silver $(Ag)$,and Platinum $(Pt)$.
Iron $(Fe)$,Calcium $(Ca)$,and Magnesium $(Mg)$ are reactive metals that readily react with oxygen and moisture to form oxides or other compounds.
Therefore,Platinum is the correct answer.

(C) The reactivity series of metals lists metals in decreasing order of their reactivity. The order is: $K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au$.
Comparing the given options:
$1$. Sodium $(Na)$ and Potassium $(K)$ are highly reactive.
$2$. Aluminum $(Al)$ is moderately reactive.
$3$. Copper $(Cu)$ is placed below hydrogen in the reactivity series,making it the least reactive among the given options.

(D) The reactivity series of metals lists metals in decreasing order of their reactivity.
According to the reactivity series: $K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au$.
Among the given options, $Sodium$ $(Na)$ is placed at the top of the reactivity series compared to $Iron$ $(Fe)$, $Zinc$ $(Zn)$, and $Copper$ $(Cu)$.
Therefore, $Sodium$ is the most reactive metal among the choices provided.

(B) Sodium aluminate is an inorganic chemical compound that acts as an effective source of aluminum hydroxide for many industrial and technical applications.
It is formed by the reaction of aluminum oxide $(Al_{2}O_{3})$ with sodium hydroxide $(NaOH)$.
The chemical reaction is: $Al_{2}O_{3} + 2NaOH \rightarrow 2NaAlO_{2} + H_{2}O$.
Therefore,the molecular formula of sodium aluminate is $NaAlO_{2}$.

(C) Aluminum oxide $(Al_{2}O_{3})$ is an amphoteric oxide,meaning it reacts with both acids and bases.
When $Al_{2}O_{3}$ reacts with a strong base like sodium hydroxide $(NaOH)$,it forms sodium aluminate $(NaAlO_{2})$ and water.
The balanced chemical equation for this reaction is:
$Al_{2}O_{3(s)} + 2NaOH_{(aq)} \xrightarrow{\Delta} 2NaAlO_{2(aq)} + H_{2}O_{(l)}$
Therefore,the missing product is $2NaAlO_{2}$.

(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.

(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 $B$.

(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.

(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.

(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,$2Na(s) + H_2(g) \rightarrow 2NaH(s)$.

(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.

(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 $(Sn)$.

(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 $A$.

(C) Duralumin is an alloy of aluminum $(95\%)$, copper $(4\%)$, magnesium $(0.5\%)$, and manganese $(0.5\%)$.
It is widely used in the aerospace industry for manufacturing aircraft parts due to its high strength-to-weight ratio and excellent corrosion resistance.

(B) Stainless steel is an alloy of iron,chromium,and nickel. It is highly resistant to corrosion and rust,making it the ideal material for manufacturing surgical instruments that require sterilization and durability.

(C) Pure gold is known as $24$ carat gold.
It is very soft and ductile,making it unsuitable for making jewelry in its pure form.
Therefore,it is usually alloyed with small amounts of other metals like silver or copper to make it harder.

(B) $24$ carat gold is considered pure gold.
$22$ carat gold means that it contains $22$ parts of pure gold mixed with $2$ parts of either copper or silver to make it hard enough for jewelry making.
Therefore,the correct proportion is $22$ parts pure gold and $2$ parts copper.

(D) Oxides are generally classified as acidic,basic,amphoteric,or neutral.
$CO_{2}$,$SO_{2}$,and $P_{2}O_{5}$ are non-metallic oxides that react with water to form acids,making them acidic in nature.
$N_{2}O$ (nitrous oxide),$NO$ (nitric oxide),and $CO$ (carbon monoxide) are well-known examples of neutral oxides.
Neutral oxides do not react with either acids or bases to form salts.
Therefore,$N_{2}O$ is the correct answer.

(C) Non-metals react with oxygen to form oxides that are generally acidic in nature.
$CO_{2}$ (Carbon dioxide) is an oxide of a non-metal (Carbon).
When $CO_{2}$ dissolves in water,it forms carbonic acid $(H_{2}CO_{3})$,which confirms its acidic nature.
Therefore,$CO_{2}$ is an acidic oxide.

(B) Phosphorus pentoxide $(P_4O_{10})$ is an oxide of a non-metal.
Non-metallic oxides are generally acidic in nature.
When phosphorus pentoxide reacts with water,it forms phosphoric acid $(H_3PO_4)$,which confirms its acidic character:
$P_4O_{10} + 6H_2O \rightarrow 4H_3PO_4$.
Therefore,the correct option is $B$.

(B) When zinc $(Zn)$ reacts with diluted hydrochloric acid $(HCl)$,it undergoes a displacement reaction.
In this reaction,zinc displaces hydrogen from the acid to form zinc chloride $(ZnCl_{2})$ and releases hydrogen gas $(H_{2})$.
The chemical equation for this reaction is: $Zn(s) + 2HCl(aq) \rightarrow ZnCl_{2}(aq) + H_{2}(g)$.