Mix Examples - Metals and Non-metals Questions in English

(B) Non-metals typically form acidic or neutral oxides.
$1$. Acidic oxides: These react with water to form acids. Among the given,$SO_2$ and $NO_2$ are acidic oxides.
$2$. Neutral oxides: These do not react with acids or bases to form salts. Among the given,$CO$,$H_2O$,and $N_2O$ are neutral oxides.

(A) Ores are naturally occurring minerals from which metals can be extracted profitably.
These ores are usually contaminated with earthy impurities such as soil,sand,and rocky materials.
These unwanted impurities present in the ore are collectively known as $Gangue$.

(N/A) Anodising is an electrolytic process used to increase the thickness of the natural oxide layer on the surface of metal parts,typically aluminium.
During this process,a clean aluminium article is made the anode and is electrolysed with dilute sulphuric acid.
The oxygen gas evolved at the anode reacts with the aluminium to form a thicker,protective aluminium oxide layer,which makes the metal resistant to corrosion.

(N/A) Electron-dot structure of sodium: $Na \cdot$
Electron-dot structure of chlorine atom: $: \ddot{Cl} \cdot$
Sodium $(Na)$ has $1$ valence electron. It loses this electron to attain the stable electronic configuration of the nearest noble gas,neon $(Ne)$.
Chlorine $(Cl)$ has $7$ valence electrons. It gains the electron lost by sodium to complete its octet and achieve the stable electronic configuration of the nearest noble gas,argon $(Ar)$.
The electrostatic force of attraction between the positively charged sodium ion $(Na^+)$ and the negatively charged chloride ion $(Cl^-)$ results in the formation of an ionic bond (also called an electrovalent bond).
Compounds formed by ionic bonds have high melting points because a large amount of energy is required to break the strong electrostatic forces of attraction between the oppositely charged ions.

(A) $(i)$ Magnesium reacts with very dilute nitric acid to produce magnesium nitrate and hydrogen gas.
$Mg(s) + 2HNO_3(aq) \longrightarrow Mg(NO_3)_2(aq) + H_2(g)$
$(ii)$ Steam reacts with red hot iron to form iron $(II, III)$ oxide and hydrogen gas.
$3Fe(s) + 4H_2O(g) \longrightarrow Fe_3O_4(s) + 4H_2(g)$

(N/A) $(i)$ Metals conduct electricity because they possess free electrons that are mobile. Consequently,they offer minimal resistance to the flow of electric current.
$(ii)$ The reaction between iron $(III)$ oxide $(Fe_{2}O_{3})$ and aluminium is highly exothermic. The heat released is sufficient to produce molten iron,which fills the cracks in machine parts. This is known as the thermite reaction:
$Fe_{2}O_{3}(s) + 2Al(s) \xrightarrow{\text{Heat}} 2Fe(l) + Al_{2}O_{3}(s)$
$(iii)$ These metals are stored under oil for two primary reasons:
$(a)$ They are highly reactive and can spontaneously catch fire upon contact with atmospheric oxygen.
$(b)$ They react readily with moisture and carbon dioxide in the air,forming a layer of oxides or carbonates on their surface.

(N/A) $(i)$ When a metal is heated,its atoms gain energy and vibrate more vigorously. This energy is transferred to the free electrons,which move through the metal lattice. These electrons transfer their kinetic energy to other atoms and electrons throughout the structure,making metals good conductors of heat.
$(ii)$ Pure gold,known as $24$ carat gold,is extremely soft and malleable. It is not suitable for making jewellery as it would easily deform. Therefore,a small amount of silver or copper is added to create an alloy,which makes the gold harder and more durable.
$(iii)$ Non-metals are electronegative and act as electron acceptors. To displace hydrogen from dilute acids,a substance must be able to donate electrons to $H^{+}$ ions to form $H_2$ gas. Since non-metals cannot provide electrons,they are unable to displace hydrogen from dilute sulphuric acid.

(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,copper $(Cu)$ is more reactive than silver $(Ag)$.
Therefore,copper can displace silver from its salt solution $(AgNO_3)$.
The chemical equation is: $Cu(s) + 2AgNO_3(aq) \rightarrow Cu(NO_3)_2(aq) + 2Ag(s)$.
In other options,the metal added is less reactive than the metal present in the salt solution,so no reaction will occur.

(A) To prevent an iron frying pan from rusting,we must consider the nature of the object.
Applying paint or grease is not suitable for a frying pan because these substances are not food-safe and would contaminate the food during cooking.
Applying a coating of zinc (galvanization) is also generally avoided for cooking utensils because zinc can react with acidic foods and leach into them,which is harmful.
However,in the context of standard multiple-choice questions regarding rust prevention,if we must choose the most appropriate method for a cooking surface,we often look for methods that do not involve toxic coatings.
Actually,none of the options provided are ideal for a frying pan. However,if this is a standard textbook question,it often expects 'Applying a coating of zinc' as a general rust prevention method,but for a frying pan,the most practical method is keeping it dry or seasoning it with oil. Given the options,if we must select one,'Applying a coating of zinc' is a standard method for iron,though not for frying pans. If the question implies general iron objects,all would work. Given the specific mention of a 'frying pan',this question is technically flawed as none are ideal. Assuming the question asks for general rust prevention: 'All of these' is the most logical choice for general iron items.

(B) $1$. Carbon forms $CO_2$,which is a gas at room temperature and has a low melting point.
$2$. Calcium reacts with oxygen to form $CaO$ (calcium oxide),which is an ionic compound with a very high melting point. $CaO$ is soluble in water,forming calcium hydroxide $(Ca(OH)_2)$.
$3$. Silicon forms $SiO_2$,which is a covalent network solid with a high melting point but is insoluble in water.
$4$. Iron forms $Fe_2O_3$,which has a high melting point but is insoluble in water.
$5$. Therefore,the element is Calcium.

(C) Food cans are coated with tin because zinc is more reactive than tin.
When food (which often contains organic acids) comes into contact with a zinc coating,the zinc can react with the acids to form toxic metal salts,which can contaminate the food.
Tin is less reactive than zinc and does not react easily with the acids present in food,making it a safer choice for coating food containers.

(D) An alloy is a homogeneous mixture of two or more metals or a metal and a non-metal.
When an alloy is formed,the regular arrangement of atoms in the pure metal lattice is disrupted by the addition of other atoms.
This disruption hinders the movement of free electrons,which are responsible for electrical conduction,thereby decreasing the electrical conductivity compared to the pure metal.
Additionally,the presence of foreign atoms creates lattice distortions that require more energy to overcome during the phase transition from solid to liquid,which typically results in a lower melting point compared to the pure metal (though this can vary,the general property of alloys is lower conductivity and lower melting point than the base metal).

(A) Brass is a metallic alloy that primarily consists of $Copper$ $(Cu)$ and $Zinc$ $(Zn)$.
It typically contains about $60-80\%$ copper and $20-40\%$ zinc,depending on the desired properties.
Copper and tin form bronze,while copper and nickel form cupronickel.

(B) Solder is an alloy composed of lead $(Pb)$ and tin $(Sn)$.
It is characterized by a very low melting point compared to the pure metals from which it is made.
Due to this low melting point,it is specifically used for soldering or joining electrical wires together in circuits,as it can be easily melted with a soldering iron without damaging the delicate components or insulation of the wires.

(C) Galvanisation is a process of applying a protective layer of zinc to steel or iron to prevent rusting.
Rusting is the oxidation of iron in the presence of oxygen and moisture.
By coating the surface with zinc,the metal is protected from direct contact with the atmosphere,thereby preventing corrosion.

(D) Stainless steel is an alloy of iron.
To improve its properties,such as corrosion resistance and hardness,iron is mixed with other metals.
The primary metals added to iron to produce stainless steel are $Nickel$ and $Chromium$.
Carbon is also added in small amounts to increase the strength of the alloy.

(A) Bronze is a metallic alloy consisting primarily of copper,usually with tin as the main additive.
It typically contains about $88\%$ copper and $12\%$ tin.
Other elements such as aluminum,manganese,nickel,or zinc are sometimes added to produce different properties.
Therefore,the correct composition is copper and tin.

(B) Highly reactive metals such as Sodium $(Na)$ and Calcium $(Ca)$ are placed at the top of the reactivity series.
These metals have a very high affinity for oxygen and cannot be reduced by carbon or other common reducing agents.
Therefore,they are extracted by the electrolytic reduction of their molten chloride salts (e.g.,$NaCl$ and $CaCl_2$).
Metals like Iron $(Fe)$ and Copper $(Cu)$ are less reactive and are typically extracted by reduction with carbon or other chemical methods.
Thus,only $(i)$ and $(ii)$ are obtained by the electrolysis of their molten chlorides.

(C) Magnesium $(Mg)$ does not react with cold water. It reacts with hot water to form magnesium hydroxide $(Mg(OH)_2)$ and hydrogen gas $(H_2)$. It also reacts with steam to form magnesium oxide $(MgO)$ and hydrogen gas $(H_2)$. Therefore,the statement that it reacts with cold water to form magnesium oxide is incorrect.

(D) In an electrolytic cell,electrical energy is used to drive a non-spontaneous chemical reaction.
By definition,the electrode where reduction occurs is the cathode,and in an electrolytic cell,the cathode is connected to the negative terminal of the external power source,making it negatively charged.
The electrode where oxidation occurs is the anode,and in an electrolytic cell,the anode is connected to the positive terminal of the external power source,making it positively charged.
Therefore,the correct characteristics are $(iii)$ Positively charged anode and $(iv)$ Negatively charged cathode.

(A) In the process of electrolytic refining of metals like zinc,an impure metal rod is used as the anode and a thin strip of pure metal is used as the cathode.
When an electric current is passed through the electrolyte (a salt solution of the metal),the impure metal from the anode dissolves into the electrolyte.
Simultaneously,an equivalent amount of pure metal from the electrolyte is deposited on the cathode.
Therefore,during the electrolytic refining of zinc,pure zinc gets deposited on the cathode.

(B) The properties described are characteristic of alkali metals.
$1$. Alkali metals like $Na$ (Sodium) and $K$ (Potassium) are soft enough to be cut with a knife.
$2$. They are highly reactive with oxygen in the air,forming oxides,and thus are stored in kerosene to prevent contact with air and moisture.
$3$. They react vigorously with water to produce hydrogen gas and metal hydroxides.
Among the given options,$Na$ (Sodium) fits all these criteria.

(C) Ionic compounds are formed by the electrostatic attraction between oppositely charged ions.
In the solid state,these ions are held in a rigid crystal lattice structure and are not free to move.
Because electrical conductivity requires the movement of charged particles,ionic compounds do not conduct electricity in the solid state.
However,when dissolved in water or in a molten state,the crystal lattice breaks down,allowing the ions to move freely,which enables them to conduct electricity.
Therefore,the property not exhibited by ionic compounds is electrical conductivity in the solid state.

(C) Metals that are very low in the reactivity series are found in their native (free) state in nature because they are highly unreactive.
These metals include gold $(Au)$,silver $(Ag)$,and platinum $(Pt)$.
In the given list:
$(i)$ $Au$ (Gold) is a noble metal and exists in a native state.
$(ii)$ $Cu$ (Copper) is found in both native and combined states (as sulfides or oxides).
$(iii)$ $Ag$ (Silver) is a noble metal and exists in a native state.
$(iv)$ $Fe$ (Iron) is highly reactive and is always found in a combined state (as oxides,carbonates,or sulfides).
Therefore,$(i)$ and $(iii)$ are the correct metals that exist in their native state.

(A) Electrolytic refining is a process used to purify metals that are obtained from their ores.
Metals like copper $(Cu)$,gold $(Au)$,silver $(Ag)$,and zinc $(Zn)$ are commonly refined using the electrolytic refining method.
In this process,an impure metal is made the anode,and a pure strip of the same metal is made the cathode.
Metals like sodium $(Na)$ and potassium $(K)$ are highly reactive and are extracted by the electrolytic reduction of their molten chlorides,not by electrolytic refining of the metal itself.
Therefore,$(i)$ $Au$ and $(ii)$ $Cu$ are the metals refined by electrolytic refining.

(B) When silver articles are exposed to air for a long time, they react with sulfur compounds present in the air, such as hydrogen sulfide $(H_{2}S)$.
This chemical reaction leads to the formation of a black coating of silver sulfide $(Ag_{2}S)$ on the surface of the silver.
The chemical equation for this process is: $2Ag + H_{2}S \rightarrow Ag_{2}S + H_{2}$ (or more accurately in the presence of oxygen: $4Ag + 2H_{2}S + O_{2} \rightarrow 2Ag_{2}S + 2H_{2}O$).

(C) Galvanisation is a metallurgical process used to prevent the corrosion of iron or steel.
In this process,a thin layer of $Zinc$ is applied to the surface of the iron or steel object.
$Zinc$ is more reactive than iron,so it acts as a sacrificial anode,protecting the underlying iron from oxidation even if the coating is scratched.
Therefore,the correct answer is $Zinc$.

(FALSE) The statement is False.
Non-metals generally do not react with dilute acids to produce hydrogen gas. This is because non-metals are electron acceptors and cannot displace hydrogen ions $(H^+)$ from acids to form hydrogen gas $(H_2)$. Metals,on the other hand,are electron donors and can displace hydrogen from acids.

(TRUE) The statement is True.
When metals like magnesium $(Mg)$,aluminium $(Al)$,zinc $(Zn)$,and lead $(Pb)$ are exposed to air at ordinary temperatures,they react with atmospheric oxygen to form a thin,protective layer of their respective metal oxides on their surface.
This oxide layer is non-porous and adheres strongly to the metal surface,acting as a barrier that prevents further oxidation or corrosion of the underlying metal.

(TRUE) The statement is True.
Explanation: When a solid piece of iron is heated,it does not burn because the surface area exposed to oxygen is small. However,when iron is in the form of fine filings,the surface area exposed to oxygen is significantly increased. This allows for a rapid reaction with oxygen in the flame,causing the iron filings to burn vigorously.

(TRUE) The statement is True.
When copper is heated in air, it does not burn (i.e., it does not produce a flame). However, it reacts with atmospheric oxygen to form copper $(II)$ oxide, which appears as a black-coloured layer on the surface of the metal.
The chemical reaction is: $2Cu(s) + O_2(g) \xrightarrow{\Delta} 2CuO(s)$ (Copper $(II)$ oxide).

(FALSE) False.
Silver $(Ag)$ and gold $(Au)$ are noble metals located at the bottom of the reactivity series. They are highly unreactive and do not react with oxygen even at high temperatures to form oxides.

(FALSE) False.
Nitric acid $(HNO_3)$ is a strong oxidizing agent.
When a metal reacts with $HNO_3$,the hydrogen gas produced is oxidized to water $(H_2O)$ by the nitric acid,and the nitric acid itself gets reduced to nitrogen oxides such as $N_2O$,$NO$,or $NO_2$.
Therefore,hydrogen gas is generally not evolved during this reaction,except in the case of very dilute nitric acid reacting with magnesium $(Mg)$ or manganese $(Mn)$.

(FALSE) The statement is False.
Copper $(Cu)$ is a less reactive metal than hydrogen in the reactivity series. Therefore,it cannot displace hydrogen from dilute hydrochloric acid $(HCl)$. Consequently,no reaction occurs between copper and dilute $HCl$.

(TRUE) True.
Ionic compounds are composed of ions (cations and anions) held together by strong electrostatic forces of attraction.
When an ionic compound is dissolved in water,these forces are weakened,allowing the ions to become free to move.
When electricity is passed through this aqueous solution,the cations (positively charged ions) move towards the cathode (negatively charged electrode) and the anions (negatively charged ions) move towards the anode (positively charged electrode),thereby conducting electricity.

(TRUE) The statement is True.
Minerals are naturally occurring inorganic substances found in the earth's crust. They have a definite chemical composition and a crystalline structure. Elements or compounds that occur naturally in the earth's crust are indeed defined as minerals.

(TRUE) True.
An ore is a type of rock that contains sufficient minerals with important elements,including metals,that can be economically extracted from the rock.
While all ores are minerals,not all minerals are ores,because some minerals may contain a metal but it may not be profitable or feasible to extract it.

(A) Alumina is the common name for aluminum oxide.
Its chemical formula is $Al_{2}O_{3}$.
It is a naturally occurring oxide of aluminum and is the primary ore of aluminum, known as bauxite when impure.

(B) Roasting is a metallurgical process in which a sulfide ore is heated strongly in the presence of excess air to convert it into its oxide form.
In the reaction $2ZnS_{(s)} + 3O_{2(g)} \xrightarrow{\Delta} 2ZnO_{(s)} + 2SO_{2(g)}$,zinc sulfide $(ZnS)$ is heated in the presence of oxygen to form zinc oxide $(ZnO)$ and sulfur dioxide $(SO_2)$.
Therefore,this reaction represents roasting.
Option $A$ represents calcination (heating carbonate ore in limited air).
Option $C$ represents reduction of metal oxide using carbon.
Option $D$ represents the reaction of metal with steam.

(C) An alloy is a homogeneous mixture of two or more metals,or a metal and a non-metal.
$24$ carat gold is pure gold,which is very soft and cannot be used for making jewellery.
To make it hard,it is alloyed with small amounts of silver or copper.
$22$ carat gold consists of $22$ parts of pure gold and $2$ parts of either copper or silver,making it an alloy.

(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.

(B) The process of obtaining a metal from its metal oxide is known as reduction.
Metal oxides are compounds where metal is in an oxidized state.
To extract the pure metal,oxygen must be removed from the metal oxide.
This removal of oxygen is chemically defined as reduction.
Common reducing agents like carbon (coke),carbon monoxide,or more reactive metals (like aluminum in the thermite process) are used to perform this reduction.

(B) Statement $B$ is incorrect because metals generally have high melting and boiling points due to strong metallic bonding.
Statement $A$ is correct as iron rusts in the presence of moisture and oxygen.
Statement $C$ is correct as calcination is the process of heating carbonate ores in limited supply of air.
Statement $D$ is correct as a more reactive metal displaces a less reactive metal from its salt solution.

(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.

(C) The earth's crust is composed of various elements. Among all metals, $Aluminium$ is the most abundant metal, accounting for approximately $8.1\%$ of the earth's crust by weight. $Iron$ is the second most abundant metal, making up about $5.0\%$ of the crust. Therefore, the correct answer is $Aluminium$.

(B) Mercury $(Hg)$ is the metal used in thermometers.
It is a liquid at room temperature and has a high coefficient of thermal expansion,which allows it to expand and contract uniformly with temperature changes.
Additionally,it has a high boiling point and does not stick to the glass walls of the thermometer,making it ideal for measuring temperature accurately.

(C) hygroscopic substance is one that absorbs moisture from the atmosphere.
Anhydrous calcium chloride $(CaCl_2)$ is a well-known drying agent (desiccant) because it readily absorbs water vapor from the air,making it hygroscopic.
Cryolite,Feldspar,and Slag do not possess this property under normal atmospheric conditions.

(D) To determine which metal is the lightest, we compare their densities:
$1$. Copper $(Cu)$: Density $\approx 8.96 \, g/cm^3$
$2$. Silver $(Ag)$: Density $\approx 10.49 \, g/cm^3$
$3$. Lead $(Pb)$: Density $\approx 11.34 \, g/cm^3$
$4$. Magnesium $(Mg)$: Density $\approx 1.74 \, g/cm^3$
Comparing these values, Magnesium has the lowest density among the given options, making it the lightest metal.