Explore topic-wise InterviewSolutions in .

This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

5951.

Fe and Al_(2)O_(3) is used in the thermite welding

Answer»


Solution :Al powder and `Fe_(2)O_(3)` is used in THERMITE welding.
Discussion
5952.

Fats + NaOH to ________ + Glycerol . One of the product formed in this reaction is

Answer»

SOAP
CLOTH
PAPER
wood

Solution :soap
Discussion
5953.

State true or false: The d-block elements are called transitionelements.

Answer»

SOLUTION :FALSE . f-block ELEMENTS aremetals.
Discussion
5954.

Extraction of metals always involves reduction processes. Explain.

Answer»

Solution :METALS are always available in nature in the form of ORES in which the metal remains as cation. EXTRACTION of the metal from the ore is to GET the metal in its elemental state. For this purpose, any metal compound is always required to be reduced.
Discussion
5955.

Express this number in standard form 228.24 xx 10^(-3)

Answer»

2282.4
2.2824
0.22824
All of the above

Answer :C
Discussion
5956.

Express this number in standard form 1.234 xx10^(3)

Answer»

1234
12.34
1.234
None

Answer :A
Discussion
5957.

Express this number in scientific notation. 0.00345

Answer»

`345 xx 10^(-5)`
`345 xx 10^(-4)`
`345 xx 10^(-3)`
`345 xx 10^(-1)`

Answer :A
Discussion
5958.

Explain why the surface of some metals acquires a dull appearance when exposed to air for a long time.

Answer»

Solution :The surface of some metals acquires a dull appearance when exposed to AIR for a LONG TIME DUE to the formation of a thin layer of oxide, carbonate or sulphide on their surface by the slow action of the various gases present in air.
Discussion
5959.

Explain why the strengths of strong acids and strong bases cannot be dtermined in water. How is it possible to compare the acidic strengths in acetic acid ?

Answer»

SOLUTION :In presence of any strong acid, water acts as a proton acceptor. In presence of any strong base, water acts as a proton donor. Therefore, the ability of a strong acid to donate protons is determined by the proton accepting CAPACITY of water and not on the acid. Hence, all strong acids SHOW EQUAL tendency to donate protons. Same thing happens with bases ALSO. When the strong acids are taken in acetic acid, which is a very weak proton acceptor than water, the different acids donate protons to different extents. Therefore, the strengths of various strong acids can be compared in acetic acid.
Discussion
5960.

Explain why, the galvanised iron article is protected against rusting even if the zinc layer is broken.

Answer»

Solution :The galvanised IRON article is protected against rusting even if the zinc layer is broken because zinc is more EASILY oxidised than iron, SO when zinc layer on the SURFACE of galvanised iron article is broken, then zinc continues to CORRODE but iron article does not corrode or rust.
Discussion
5961.

Explain why the following statements are not correct? i) All groups contain both metals and non metals. ii) In group 1, reactivity decreases with increase in atomic number. iii) Elements in a period become more metallic with increasing atomic number. iv) Atoms of elements in the same group have the same number of electrons.

Answer»

Solution :i) All groups do not contain both metals and non metals. GROUP I and II contain only metals.
ii) In group I. reactivity INCREASES with increase in atomic number. This is because as the SIZE of the atoms increases, the valence SHELL electrons can be easily removed.
iii) The metallic character decreases in a period with increase in atomic number. This is because across the period, the size of the atom decreases and the valence shell electron are held more tightly.
iv) In a neutral atom the number of electrons is equal to the number of protons. In a group the atomic number as we move down.
Discussion
5962.

Explain why sodium is more reactive than lithium.

Answer»

SOLUTION :Sodium is more reactive than lithium because sodium is larger in size. Outermost electrons are lesstightly HELD in sodium than in lithium. As a result, sodium LOSES its outermost electron more easily than lithium. HENCE, it is more reactive than lithium.
Discussion
5963.

Explain why phosphorous acid is not a tribasic acid like phosphoric acid through both acids contain three hydrogen in their molecules

Answer»

Solution :(i) comparison of the structures of TWO acids
(ii) condition required for a substance to behave like an ACID in its aqueous solution
(iii) comparison of POSITIONS of hydrogen atoms present in phosphorus acid to that present in phosphoric acid
(iv) relation between the positions of hydrogen in the respective molecules and its replaceability
(v) relation between the number of REPLACEABLE
Discussion
5964.

Explain why Nitrogen in soil is called saturated solution in nature?

Answer»

SOLUTION :Nitrogen in SOIL is an example for SATURATED solution in nature. Soil cannot store more Nitrogen than it can HOLD.
Discussion
5965.

Explain why no indicator can be used for the titration between formic acid and ammonium hydroxide

Answer»

SOLUTION :In acid-base titrations, the end POINT is detected by the use of a substance called acid-base indicator. Acid-base indicator exhibits a sharp change in its colour at the end point. The EXPERIMENTALLY determined point of completion of an acid-base TITRATION is called end point. for the titration between a weak acid and weak base, there is no sharp change in PH. Hence, no indicator can be used
Discussion
5966.

Explain why it is difficult to wash clothes with soap when water is hard. How do detergents help in overcoming this problem?

Answer»

Solution :In hard water, soap REACTS with CALCIUM and magnesium salts which are present in hard water and FORM insoluble substances called scum.
Detergents are ammonium or sulphonate salts of long CHAIN carboxylie acids. The charged end of these COMPOUNDS do not form insoluble precipitates with caleium and magnesium ions in hard water.
Discussion
5967.

Explain why for diluting an acid, concentrated acid is added to water and not water to concentrated acid ?

Answer»

Solution :This is because the process of dissolution of an acid in WATER is highly EXOTHERMIC process. For dilution concentrated acid, the acid must be added slowly to water with constant stirring. If water is added to acid, the heat generated may CAUSE the mixture to SPLASH out and cause burns. The glass container may also break due to excessive LOCAL heating.
Discussion
5968.

Explain why carbon tetrachloride does notdissolve in water.

Answer»

Solution :`C Cl_(4)` is a non-polar covalent COMPOUND and henceis insoluble in polar SOLVENTS like WATER.
Discussion
5969.

Explain why carbon forms compounds mainly by covalent bond. Explain in brief two main reasons for carbon forming a large number of compounds. Why does carbon form strong bonds with most other elements ?

Answer»

Solution :Carbon has no TENDENCY to lose electrons easily. Similarly it has no tendency to gain electrons. It completes its octet by sharing the electrons with other atoms. Therefore, carbon forms compounds mainly by covalent bond.
Two main reasons for carbon forming a large NUMBER of compounds are given below : Catenation : It is the property of carbon to link with other carbon atoms to form straight chain, branched chain or cyclic compounds. Thus, carbon forms a large number of compounds containing 2, 3, 4, 5,....etc., carbon atoms.
Tetravalency: Carbon has four electrons in the outermost SHELL. It shares these four electrons with four electrons from four other monovalent atoms. Carbon has the tendency to form bonds with hydrogen, oxygen, nitrogen and halogens. This increases the number of compounds of carbon.
Carbon forms STRONG bonds with most other elements : This is because carbon has a small atomic size. It can hold strongly the four PAIRS of electrons that it shares with other atoms. Therefore, it forms strong bonds with other elements.
Discussion
5970.

Explain why carbon forms compounds mainly by covalent bonds. Explain in brief two main reasons for carbon forming a large number of compounds. Why does carbon form strong bonds with most other elements.

Answer»

Solution :(i) Carbon has 4 ELECTRONS in its outermost shell and needs to pain or lose 4 electrons to attain noble gas configuration. Losing or gaining 4 electrons is not possible due to energy considerations, hence it SHARES electrons to form covalent bonds.
Two reasons for large number of carbon compounds are:
(ii) Catenation The unique ability of carbon to form bonds with other atoms of carbon giving rise to long chains of DIFFERENT types of conipounds.
(iii) Tetravalency : Since carbon has a valency of 4, it is capable of bonding with four other atoms of carbon or atoms of elements like oxygen, hydrogen, nitrogen, sulphur, CHLORINE, ETC.
The reason for the formation of strong bonds by carbon is its small size which enables the nucleus to hold on to the shared pairs of electrons strongly.
Discussion
5971.

Explain why carbon forms compounds mainly by covalent bond. Explain in brief two main reasons for carbon forming a large number of compounds. Why does carbon form strong bonds sith most other elements?

Answer»

SOLUTION :Carbon has 4 electrons in its outermost shell, and needs to gain or lose 4 electrons to attain noble gas CONFIGURATION. Losing or gaining 4 electrons is not possible DUE to energy CONSIDERATIONS, hence it shares electrons to form covalent bonds.
Two reasons for large number of carbon compounds:
(i) Catenation: The unique abilityof carbon to form bonds with other atoms of carbon giving rise to long chains of different types of compounds.
(ii) Tetravalency: Since carbon has a valency of 4, it is capable of bonding with four other atoms of carbon or atoms of elements like oxygen, hydrogen, nitrogen, sulphur, chlorine, ETC.
Carbon forms strong bonds with most other elements because of its small size which enables the nucleus to hold on to the shared pairs of electrons strongly.
Discussion
5972.

Explain why calcium metal after reacting with water starts floating on its surface. Write the chemical equation for the reaction.

Answer»

SOLUTION :Calcium starts FLOATING because the bubbles of hydrogen gas FORMED sticks to the surface of the metal.
`Ca + 2H_(2)O rarr Ca(OH)_(2) + H_(2)`
Discussion
5973.

Explain why atomic number is more important than atomic mass in determining chemical properties.

Answer»

Solution :Chemical reactions depend upon the type of bonding in the REACTANTS which, in tum, depends upon the number of ELECTRONS in the OUTERMOST shell. The number of electrons in the outermost shell isgiven by atomic number. Therefore, atomic number is more important than atomic MASS in DETERMINING chemical properties.
Discussion
5974.

Explain why an aqueous solution of ammonium chloride is acidic in nature .

Answer»

Solution :AMMONIUM chloride `(NH_(4)Cl)` is the salt of a strong ACID, HYDROCHLORIC acid (HCL), and a WEAK base ammonium hydroxide `(NH_(4)OH)` , so an aqueous solution of ammonium chloride is acidic in nature.
Discussion
5975.

Explain why an aqueous solution of sodium sulphate is neutral while an aqueous of sodium carbonate is basic in nature.

Answer»

SOLUTION :SODIM sulphate is a NEUTRAL salt because it is made from STRONG acid and strong base.
Sodium carbonate is a BASIC salt because it is made from strong base and weak acid.
Discussion
5976.

Explain why a solution of cane sugar doesnot conduct electricity where as a solutionof sodium chloride is a good conductor.

Answer»

Solution : Solution of cane sugar comprises of sugarmolecules only. It does not contain ions hence does not CONDUCT ELECTRICITY whereas solution of sodium chloride SPLITS into ions. These ions make sodium chloride a good conductor of electricity.
Discussion
5977.

Explain what is galvanization. What purpose is served by it ?

Answer»

Solution :Galvanization is a METHOD of protecting STEEL and IRON from resuting by coating them with a thin layer of ZINC. The galvanized article is PROTECTED against rusting even if the zinc coating is broken.
Discussion
5978.

Explain Wet Corrosion.

Answer»

Solution : (i) The corrosive action in the presenee of moisture is called WET corrosion
(ii) It occurs as a RESULT of electrochemical reaction of METAL with water or aqueous solution of salt or acids or bases.
Discussion
5979.

Explain what happens if bauxite containing iron oxide and silica as impurities is directly subjected to the process of electrolytic reduction without prior purification.

Answer»

Solution :Crude bauxide CONTAINS iron oxide and silica as IMPURITIES. If any iron is present in the bauxite, it will GET deposited at the CATHODE in prefernce to ALUMINIUM because iron is less electropositive than aluminium.
Discussion
5980.

Explain : We cannot classify the elements according to their physical properties alone.

Answer»

Solution : Exceptions of METALLIC elements :
( 1 ) All metals EXCEPT MERCURY are solids at room temperature, while mercury is a liquid at room temperature. (2) Generally, metals have high melting points but Galium and Caesium have very low melting points. (3 ) ALKALI metals (Lithium, sodium, potassium) are very soft hence, they can be cut with a KNIFE, while other metals cannot be cut with a knife.
Exceptions of non-metallic elements :
(1) Generally, non-metals exist as solids or gases at room temperature while bromine is a liquid (2) Non-metals does not possess lustre, but iodine is the only non-metal which possesses lustre. (3) Non-metals have low melting points, but the diamond, an allotrope of carbon possesses very high melting point. (4) Non-metals are generally non-conductors of electricity, but the graphite, an allotrope of carbon is the only non-metal which conducts electric current.
Discussion
5981.

Explain two ways by which food industry prevents rancidity.

Answer»

Solution :(a) Rancidity can be PREVENTED by ADDING antioxidant to good CONTAINING fat and oil
Eg. : (i) By adding BHA - Butylated hydroxy ANISOLE
(ii) It can be prebvented by packing food containing fat and oil in nitrogen gas.
Discussion
5982.

Explain : Thermit process (reaction)

Answer»

Solution : More reactive metals displace less reactive metals from the solution of their compounds. Such displacement reactions are highly exothermic. The amount of HEAT evolved is so large that the metals are PRODUCED in the MOLTEN state. This reaction is called as the thermit reaction.For example, the reaction of iron (III) oxide `(Fe_2O_3)`with aluminium forms molten FE, which is used to join railway tracks or cracked machine parts.
Discussion
5983.

Explain the variation of lonisation energy along the group and period.

Answer»

SOLUTION : (i) As the atomic size DECREASES from left to right in a period, more energy is required to REMOVE the electrons.So, the ionisation energy increases ALONG the period.
(ii) Down the group, the atomic size increases and hence the valence electrons are loosely bound.They require relatively less energy for the removal.Thus, ionisation energy decreases down the group in the PERIODIC table.
Discussion
5984.

Explain the variation of atomic radius (i)across the period (ii) along the group

Answer»

Solution :ACROSS the PERIOD , the atomic RADIUSOF elementsdecreaseswhereasalong the groups , the atomic radiusincreases.
Discussion
5985.

Explain the variation in the following properties of the elements in the periodic table. (i) Atomic radius in the periodic table (ii) Metallic character in a period (iii) Valency in a group.

Answer»

SOLUTION :(i) For ANSWER, CONSULT section 5.5.
(II) For answer, consult section 5.5.
(iii) For answer, consult section 5.5.
Discussion
5986.

Explain the variation in basic strengths of hydrises of VA group elements

Answer»

Solution :(i) requisite for basic nature according to Lewis theory
(ii) elements present in group VA
(iii) number of lone pairs present in the VALENCE shell of the elements of group VA
(iv) CONCEPT of BASE according to Bronsted-Lowry theory
(v) comparison of the size of the above elements
(vi) RELATION between the size of the ELEMENT and tendency of accepting the proton
(vii) comparison of stability of the respective hydrides of the elements of group VA
Discussion
5987.

Explain the use of alcohol as a fuel.

Answer»

Solution :Sugarcane PLANTS are one of the most efficient convertors of sunlight into chemical ENERGY.
Sugarcane juice is used to prepare molasses which on fermentation gives alcohol (ethanol).
Some countries now use alcohol (ethanol) as an additive in PETROL since it is a cleaner fuel which gives RISE to only carbon dioxide and water on burning in SUFFICIENT air (oxygen).
Discussion
5988.

Explainthe typesofdoubledisplacementreactionswithexamples.

Answer»

Solution :Thereare twomajorclassesof doubledisplacementreactions. Theyare
Precipitationreactions :
(i)Whenaqueoussolutionsoftwocompoundsare MIXED , if theyreacttoforman insolublecompound, if theyreacttoformand insolublecompoundanda solublecompound, then itis calledprecipitainreaction .
(ii )E .gWHentheclearaqueoussolutionsofpotassiumiodideand lead(II )niyrate aremixed , adoubledisplacementreactiontakesplacebetweenthem .
`Pb(NO _(3) )_(2(AQ))+2KI_((aq))to PbI_(2(s)) +2 KNO_(3(aq))`
NeutralizationReactions :
(i )Acidreactswith thebasetoforma saltandwater .
(ii) It iscalledneutralizationreactionas bothacidand baseneutraliseeachother
Acid+ Base `to`Salt+Water
`HCI_((aq))+NaOH_((aq)) toNaCl_((aq)) +H_(2) O_((l))`
Discussion
5989.

Explain the types of double displacement reactions with examples.

Answer»

Solution :There are two major CLASSES of double displacement reactions .They are,
(i)Precipitation Reactions
When aqueous solutions of two compounds are mixed ,if they REACT to form an insoluble compound and a SOLUBLE compound,then is called precipitation reaction.
`Pb(NO_(3))_(2(aq))+2Kl_((aq))toPbI_(2)darr+2KNO_(3(aq))`
(ii)Neutrlisation Reactions
Another type of displacement reaction in which the ACID reacts with the base to form a salt and water.It is called .NEUTRALISATION reaction. as both acid and base neutralize each other.
`NaOH_((aq))+HCl_((aq))toNaCl_((aq))+H_(2)O_((1))`
Discussion
5990.

Explain the types of corrosion .

Answer»

Solution :Typesof Corrosion :
Dry Corrosion or Chemical Corrosion :
(i) Corrosiveaction in the absenceof moisture .
(ii) It is the PROCESS of a chemical attack on a metal by a corrosiveliquids or gasessuch as `O_2,N_2,SO_2,H_2S` etc .
(III) It occursat high temperature .
WET Corrosion or Electrochemical Corrosion :
(i) Corrosiveaction in the PRESENCEOF moisture .
(ii) It occursas a resultof electrochemicalreaction of metal with water or aqueoussolution of saltor acids or bases .
Discussion
5991.

Explain the types of alloys .

Answer»

Solution : Bases on the presence or absence of IRON alloys can be callsified into :
* FERROUS alloys : Contains iron as a MAJOR COMPONENT .
A few examples of Ferrous alloys are stainless steel . Nickel steel etc.
Non- ferrous alloys: These alloys do not contains Iron as a major component.
for example, Aluminium alloy, COPPER alloy etc.
Discussion
5992.

Explain the trends of the non-metallic character in a period and a group.

Answer»

SOLUTION :Electronegative ELEMENTS possesses nonmetallic character.
Non-metals have a tendency of GAINING or sharing the electrons during bond FORMATION process.
Trend of the non-metallic character in a group :
On moving down the any group, the non-metallic character decreases.
Trend of the non-metallic character in a period:
On moving from left to right in a period, the effective nuclear charge experienced by valence electrons increases.
Therefore, the tendency to attract electrons will increase.
THUS, non-metallic character increases in a period on moving from left to right.
Discussion
5993.

Explain the trends of the metallic character in a period and a group.

Answer»

Solution :ELECTROPOSITIVE elements possesses metallic character.
Metals have a strong tendency of losing the electrons during bond FORMATION process.
Trend of the metallic character in a group :
On moving down in a group, the effective nuclear CHARGE experienced by valence electrons decreases because the outermost electrons are far away from the nucleus. Therefore tendency of the element to lose electrons increases and electrons can be LOST easily. Hence, the metallic character increases on moving down in a group.
Table 14: VARIATION in metallic character of the elements of group1

Metallic elements possess 1, 2 or 3 electrons in their outermost shells.
Trend of the metallic character in a period :
On moving from left to right in a period, the effective nuclear charge experienced by valence electrons increases.
Therefore, the tendency to lose electrons will decrease.
Thus, metallic character decreases in a period on moving from left to right.
Elements of second period :
`underset("Metals")ubrace(Li""Be)""underset("Non-metals")ubrace(B""C""N""O""F)`
Discussion
5994.

Explain the three types of decomposition reaction with the help of balanced chemical equation for each.

Answer»

SOLUTION :THERMAL Decomposition
`UNDERSET("lime stone")(CaCO) overset("heat")(to) underset("Quick lime")(CaO_(s)) + underset("carbondioxide")(CO_(2(g)) uarr)`
II. Photochemical decomposition
`underset("silver chloride")(2Ag Cl_((s)) ) overset("sun light")(to) underset("silver")(2Ag_((s)))+ underset(CHLORINE")(Cl_(2(g)) ) `
III.Electrolytic decomposition
`underset("water)(2H_2O) overset("electric current")(to) underset("HYDROGEN")(2H_(2(g)))+ underset("oxygen")(O_(2(g)))`
Discussion
5995.

Explain the tetravalency of carbon.

Answer»

Solution :The atomic number of carbon is 6.
Hence, the electronic configuration of carbon is written as:
`{:(""_(6)C,:,K,,L),(,,2,,4):}`
Thus, carbon has four electrons in its outermost shell.
The reactivity of any element depends upon its tendency to attain a completely FILLED outermost shell, that is, to attain noble gas configuration.
Elements forming ionic compounds achieve this by either gaining or losing electrons from their outermost shell.
Carbon atom needs to gain or lose four electrons to attain noble gas configuration (complete octet).
If carbon atom has to gain or lose electrons, then, -
( 1 ) It could gain four electrons forming `C^(4-)` anion. But, it would be difficult for the nucleus with six protons to hold on ten electrons, that is, four extra electrons, which is unstable.
( 2 ) It could lose four electrons forming `C^(4+)` cation. But it would REQUIRE a large amount of energy to remove four electrons leaving behind a carbon cation with six protons in its nucleus holding on just two electrons which is unstable.
In short, carbon atom cannot combine by forming electrovalent or ionic bond.
Hence, carbon, by sharing its valence electrons with other atoms of carbon or with atoms of other elements FORMS a molecule.
A bond formed by sharing of electrons of outermost shell (valence electrons) of two atoms is called covalent bond.
The shared electrons belong to the outermost shells of both the atoms and lead to both atoms attaining the noble gas configuration.
Discussion
5996.

Explain the strengths of conjugate acid base pairs of the following species. (a) HSO_(4)^(-) (b) NH_(3) (c) HS^(-) (d) ClO_(4)^(-)

Answer»

Solution :(a) `HSO_(4)^(-) RARR SO_(4)^(-2)`
`H_(2)SO_(4)` is a STRONG acid, `HSO_(4)^(-)` is a strong weak conjugate base. So, `HSO_(4)^(-)` is a strong acid, so, its conjugate base `SO_(4)^(-2)` is weak
(b) `NH_(3) + H^(+) rarr NH_(4)^(+)`
As ammonia is a weak base its conjugate acid is strong.
(C) `HS^(-) rarr S^(-2)`
`H_(2)S` is a weak acid. `HS^(-)` is a strong conjugate base So, `HS^(-)` is weak acid so its conjugate base `5^(-2)` is strong
(d) `ClO_(4)^(-) rarr HClO_(4)`
`ClO_(4)^(-)` is the conjugate base of strong acid `HClO_(4)`. As `ClO_(4)^(-)` is the conjgate base of strong acid it has to be weak
Discussion
5997.

Explain the steps for extraction of copper from its sulphide ore. Write the balanced equations involved in the process.

Answer»

Solution :(i) `2Cu_(2)S + 3O_(2) overset("Heat")RARR 2Cu_(2)O(s) + 2SO_(2)(g)`
(II) `2Cu_(2)O + Cu_(2)Soverset("Heat")rarr 6Cu(S) + SO_(2)(g)`
Discussion
5998.

Explain the significant function of each structure in human male reproductive system. OR Explain the structure and important role of placenta during pregnancy period of woman.

Answer»

Solution :(i) Testis : To PRODUCE male gametes/ sperm or male hormone/ testosterone.
(ii) Urethra : Common passage for sperm and urine.
(iii) Scrotum : To provide optimal temperature to testis for the formation of sperm.
(iv) Vas deferens : To deliver the sperms to the urethra.
(v) Prostrate glands and seminal vesicles : Tu secrete the fluid which provides nutrition and medium for transport of sperms.
(vi) Penis : Delivers the sperms into vagina of female body during mating.
OR
PLACENTA : A special tissue that helps HUMAN embryo in obtaining nutrition from mother.s BLOOD.
Structure : This is a disc which is embedded in the uterine wall which contains villi on the embryo side of the tissue, and on the mother.s side are blood spaces which surround the villi.
Function : This provides a large surface area for glucose and oxygen to pass from the mother to the embryo, and the DEVELOPING embryo will also generate waste substances which can be removed by transferring them into the mother.s blood through the placenta.
Discussion
5999.

Explain the salient features of periods in the modern periodic table.

Answer»

Solution :i) The vertical columns in the periodic table starting from top to BOTTOM are CALLED groups.
(ii) There are 18 groups in the periodic table.
(iii) As the elements present in a group have identical valence shell electronic configurations, they possess similar chemical properties.
(iv) Based on the common characteristics of elements in each group, they can be grouped as various families.
(v) The Lanthanides and Actinides which form part of Group 3 are called inner transition elements.
(vi) Except group 0, all the elements present in each groups have same valency.
(vii) The elements present in a group possess similar chemical properties.
(VIII) The physical properties of the elements in a group such as melting point, boiling point and density vary gradually.
(ix) The atoms of the group 0 elements have stable electronic configuration in their valence shells and hence they are unreactive.
Discussion
6000.

Explain the role of coke and sand added during smelting process in the extraction of copper.

Answer»

Solution :Coke is the sourece of heat in smelting and also it acts as reducing agent, which reduces `Cu_(2)O"to"CU`:
`Cu_(2)O+Cto2Cu+CO`
`SiO_(2)` combines with the IMPURITIES LIKE FeO and is removed as slag:
`FeO+SiO_(2)toFeSiO_(3)`
Discussion