Chemical Properties of Metals Questions in English

(N/A) Zinc is more reactive than copper; therefore,it will displace copper from $CuSO_4$. This reaction will take place.
$(b)$ Iron is less reactive than zinc; therefore,it cannot displace zinc from zinc sulphate. This reaction will not take place.
$(c)$ Zinc is more reactive than iron; therefore,it will displace iron from $FeSO_4$. This reaction will take place.

(B) The correct statement is that copper can displace silver from silver nitrate solution,but silver cannot displace copper from copper sulphate solution.
This is because copper is more reactive than silver,as per the reactivity series of metals.
$A$ more reactive metal can displace a less reactive metal from its salt solution.
The chemical reaction is: $Cu(s) + 2AgNO_3(aq) \rightarrow Cu(NO_3)_2(aq) + 2Ag(s)$.

(N/A) When a piece of aluminium metal is added to dilute hydrochloric acid,a displacement reaction occurs. Aluminium is more reactive than hydrogen and lies above it in the reactivity series,so it displaces hydrogen from the dilute $HCl$ solution,resulting in the evolution of hydrogen gas.
The balanced chemical equation for this reaction is:
$2Al(s) + 6HCl(aq) \longrightarrow 2AlCl_3(aq) + 3H_2(g)$

(N/A) When an active metal reacts with hydrochloric acid $(HCl)$,hydrogen gas $(H_2)$ is liberated.
To test for this gas,bring a burning candle or a matchstick near the mouth of the test tube or jar containing the gas.
The hydrogen gas burns with a characteristic '$pop$' sound,which confirms its presence.

(N/A) When dilute hydrochloric acid $(HCl)$ reacts with zinc $(Zn)$,it produces zinc chloride $(ZnCl_2)$ and releases hydrogen gas $(H_2)$.
The chemical equation for this reaction is: $Zn(s) + 2HCl(aq) \rightarrow ZnCl_2(aq) + H_2(g)$.
The gas evolved is hydrogen gas,and its molecular formula is $H_2$.

(N/A) When zinc granules are heated with sodium hydroxide solution,a chemical reaction occurs in which hydrogen gas is evolved and a salt called sodium zincate is formed.
The balanced chemical equation for this reaction is:
$Zn(s) + 2NaOH(aq) \longrightarrow Na_2ZnO_2(aq) + H_2(g)$
The main product formed in this reaction is sodium zincate $(Na_2ZnO_2)$.

(N/A) The metal is aluminium $(Al)$.
Aluminium oxide $(Al_{2}O_{3})$ is an amphoteric oxide,meaning it reacts with both acids and bases.
Reaction with dilute sulphuric acid:
$Al_{2}O_{3}(s) + 3H_{2}SO_{4}(aq) \longrightarrow Al_{2}(SO_{4})_{3}(aq) + 3H_{2}O(l)$
Reaction with dilute sodium hydroxide solution:
$Al_{2}O_{3}(s) + 2NaOH(aq) + 3H_{2}O(l) \longrightarrow 2Na[Al(OH)_{4}](aq)$ (Sodium aluminate)

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

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

(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) 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) $(i)$ 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) 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) 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 $Z = H_2$.

(A) The metal $M$ is Aluminium $(Al)$.
The oxide $Al_{2}O_{3}$ is amphoteric in nature,meaning it reacts with both acids and bases.
Reaction with dilute sulphuric acid:
$Al_{2}O_{3}(s) + 3H_{2}SO_{4}(aq) \rightarrow Al_{2}(SO_{4})_{3}(aq) + 3H_{2}O(l)$
Reaction with dilute sodium hydroxide solution:
$Al_{2}O_{3}(s) + 2NaOH(aq) + 3H_{2}O(l) \rightarrow 2Na[Al(OH)_{4}](aq)$ (or Sodium aluminate $2NaAlO_{2} + H_{2}O$)

(N/A) $Na$ reacts vigorously with cold water.
$2Na(s) + 2H_2O(l) \rightarrow 2NaOH(aq) + H_2(g)$
$(b)$ $Mg$ does not react with cold water but reacts with hot water.
$Mg(s) + 2H_2O(l) \rightarrow Mg(OH)_2(aq) + H_2(g)$
$(c)$ $Fe$ does not react with cold or hot water but reacts with steam.
$3Fe(s) + 4H_2O(g) \rightarrow Fe_3O_4(s) + 4H_2(g)$

(N/A)

Metals	Non-Metals
$1$. Burn in air to form metal oxides which are basic in nature.	$1$. Burn in air to form non-metal oxides which are acidic in nature.
$2$. React with acids to form salt and hydrogen gas.	$2$. They are electron acceptors,so they cannot produce hydrogen gas from acids.
$3$. Metals form ionic compounds with non-metals. $e.g., NaCl$.	$3$. Non-metals form covalent compounds with other non-metals. $e.g., CCl_4$.

(N/A) The most reactive element is $B$ because it displaces both $A$ and $C$ from their respective compounds.
$(b)$ The least reactive element is $C$ because it is displaced by both $A$ and $B$ in the given reactions.
$(c)$ These are displacement reactions,specifically single displacement reactions.

(N/A) The reaction which is highly exothermic and in which metal is produced in the molten state is known as the thermit reaction.
Consider the following displacement reaction:
$Fe_{2}O_{3}(s) + 2Al(s) \xrightarrow{\text{Heat}} Al_{2}O_{3}(s) + 2Fe(l) + \text{Heat}$
In this reaction,when iron $(III)$ oxide $(Fe_{2}O_{3})$ is heated with aluminium powder $(Al)$,the amount of heat evolved is so large that the iron $(Fe)$ metal is produced in a molten state.
This molten iron flows into the gaps of the railway tracks or cracked machine parts and,upon cooling,solidifies to join them together.

(N/A) An alloy is a homogeneous mixture of two or more metals,or a metal and a non-metal,which cannot be separated into its components by physical methods.
Properties that make alloys more useful than pure metals:
$(i)$ Alloys are often harder and stronger than their constituent pure metals.
$(ii)$ They are more resistant to corrosion.
$(iii)$ Their electrical conductivity is generally lower than that of pure metals.
$(iv)$ Their melting point is lower than that of pure metals.
Examples:
$(a)$ Brass (an alloy of $Cu$ and $Zn$) and Bronze (an alloy of $Cu$ and $Sn$) are not good conductors of electricity,whereas pure copper is an excellent conductor used in electrical circuits.
$(b)$ Solder (an alloy of $Pb$ and $Sn$) has a very low melting point,making it ideal for welding electrical wires together.

(N/A) $(i)$ Zinc reacts with sulphuric acid to form zinc sulphate and hydrogen gas: $Zn(s) + H_{2}SO_{4}(aq) \rightarrow ZnSO_{4}(aq) + H_{2}(g)$
$(ii)$ Zinc reacts with hydrochloric acid to form zinc chloride and hydrogen gas: $Zn(s) + 2HCl(aq) \rightarrow ZnCl_{2}(aq) + H_{2}(g)$
$(iii)$ Zinc is less reactive than aluminium,so it cannot displace aluminium from aluminium chloride: $Zn(s) + AlCl_{3}(aq) \rightarrow \text{No reaction}$
$(iv)$ Zinc reacts with sodium hydroxide to form sodium zincate and hydrogen gas: $Zn(s) + 2NaOH(aq) \rightarrow Na_{2}ZnO_{2}(aq) + H_{2}(g)$
$(v)$ Zinc reacts with concentrated nitric acid to form zinc nitrate,nitrogen dioxide,and water: $Zn(s) + 4HNO_{3}(conc.) \rightarrow Zn(NO_{3})_{2}(aq) + 2NO_{2}(g) + 2H_{2}O(l)$

(N/A) The constituents of the given alloys are as follows:
$(a)$ Brass: It is an alloy of Copper $(Cu)$ and Zinc $(Zn)$.
$(b)$ Bronze: It is an alloy of Copper $(Cu)$ and Tin $(Sn)$.
$(c)$ Solder: It is an alloy of Lead $(Pb)$ and Tin $(Sn)$.

(N/A) Most metal oxides are basic in nature. Metal oxides that are soluble in water are called basic oxides,and their aqueous solutions are known as alkalis.
$(b)$ Metals like magnesium,aluminium,and zinc react with atmospheric oxygen to form a thin,protective oxide layer on their surface. This layer is composed of the metal oxide. Its importance lies in the fact that it prevents further oxidation and corrosion of the underlying metal.
$(c)$ Alkali metals like $Li$ (Lithium),$Na$ (Sodium),and $K$ (Potassium) have a low density and weak metallic bonding due to their high electropositive character,making them soft enough to be cut with a knife.

(N/A) The rate of formation of hydrogen gas bubbles is slow with calcium (less violent) in comparison to that with potassium (more violent). The rate of hydrogen gas evolution is faster in the case of potassium,which generates enough heat to ignite the hydrogen gas.
$Ca + 2H_2O \rightarrow Ca(OH)_2 + H_2 \uparrow$
(The reaction is less vigorous,so the hydrogen gas does not catch fire.)
$(b)$ $(i)$ $Mg$ (Magnesium) or $Mn$ (Manganese).
$(ii)$ $Cu$ (Copper),$Hg$ (Mercury),$Ag$ (Silver),or $Au$ (Gold).
$(iii)$ $Fe$ (Iron),$Zn$ (Zinc),or $Al$ (Aluminium).

(N/A) Magnesium $(Mg)$ is considered a metal due to the following reasons:
$1.$ Magnesium is a hard solid with a high melting and boiling point,which are characteristic physical properties of metals.
$2.$ Magnesium atoms lose two electrons to form electropositive $(Mg^{2+})$ ions and act as good conductors of heat and electricity.
$3.$ Magnesium reacts with oxygen to form a basic oxide,which dissolves in water to form a base. This is a characteristic chemical property of metals.
Chemical equations:
$(a) 2Mg(s) + O_2(g) \rightarrow 2MgO(s)$
$(b) MgO(s) + H_2O(l) \rightarrow Mg(OH)_2(aq)$
Since magnesium exhibits these metallic properties,it is classified as a metal.

(B) Magnesium reacts with hot water to produce magnesium hydroxide and hydrogen gas $(Mg + 2H_2O \rightarrow Mg(OH)_2 + H_2)$.
As the reaction proceeds, small bubbles of hydrogen gas are produced.
These bubbles of hydrogen gas stick to the surface of the magnesium ribbon.
Due to the buoyancy provided by these gas bubbles, the magnesium ribbon starts floating on the surface of the water.

(A) Non-metals generally form acidic oxides,while metals form basic or amphoteric oxides.
$1$. Atomic number $7$ corresponds to Nitrogen $(N)$,which is a non-metal. It forms acidic oxides like $NO_2$ and $N_2O_5$.
$2$. Atomic number $3$ corresponds to Lithium $(Li)$,which is an alkali metal and forms a basic oxide $(Li_2O)$.
$3$. Atomic number $12$ corresponds to Magnesium $(Mg)$,which is an alkaline earth metal and forms a basic oxide $(MgO)$.
$4$. Atomic number $19$ corresponds to Potassium $(K)$,which is an alkali metal and forms a basic oxide $(K_2O)$.
Therefore,the element with atomic number $7$ will form an acidic oxide.

(C) When a base reacts with a metal,it produces a salt and releases $H_2$ (dihydrogen) gas.
For example,when sodium hydroxide $(NaOH)$ reacts with zinc $(Zn)$,it forms sodium zincate $(Na_2ZnO_2)$ and releases dihydrogen gas $(H_2)$.
The chemical equation is: $Zn + 2NaOH \rightarrow Na_2ZnO_2 + H_2 \uparrow$.

(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.
$3Fe(s) + 4H_2O(g) \longrightarrow Fe_3O_4(s) + 4H_2(g)$

(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.

(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.

(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.

(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.

(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.

(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.

(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 $HCl$.