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InterviewSolution
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.
| 6551. |
Describe electrolytic refining of copper with chemical equations. Draw a well as labelled diagram for it. |
Answer» Solution :Electrolytic Refining : This method is widely used as PURIFICATION of metals like zinc (Zn), copper (Cu), aluminium (Al), chromium (Cr), tin (Sn), lead (Pb), nickel (NI) and gold (Au). In this process, impure metal is used as anode, a strip of pure metal is used as cathode and SOLUBLE salt of metal is used as electrolyte. On passing ELECTRIC current through the electrolyte, cations move towards cathode, gain electrons and pure metal deposited on cathdoe. In electrolytic refining of copper the impurities LEFT behind at anode called anode and contains valuable metals such as gold and silver which can be recovered in the native state 
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| 6552. |
Describe briefly the method to obtain mercury from Cinnabar. Write the chemical equations for the reactions involved in the process. |
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Answer» Solution :When CINNABAR (HgS) is heated in the presence of air, it is first converted into MERCURIC OXIDE. `2Hg(S) + underset("(air)")(3O_(2))overset("HEAT")rarr 2HgO + SO_(2)` Mercuric oxide is then reduced to mercury on further heating. `2HgO overset("Heat")rarr 2Hg + O_(2)` |
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| 6553. |
Describe an activity with diagram to illustrate that the reaction of metal carbonates or metal hydrogen carbonates with acids produces carbon dioxide. Write the relevent equations of all the reactions that take place. Name any two forms in which calcium carbonate is found in nature. |
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| 6554. |
Describe an activity to show that the rusting of iron occurs in the presence of air and moisture. |
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Answer» Solution :(i) Take three test-tubes. Place clean iron nails ineach test-tube. (ii) Pour some water in test-tube -1, cork it. (iii) Pour water (boiled/distilled) in test-tube-2, add some oil and cork it. (iv) Put some anhydrous calcium chloride in test-tube-3 and cork it. (v) After 2-3 DAYS, we OBSERVE that the nails in test-tube 1 trust because they are exposed to air and water both, while NAIL in test-tube 2 and 3 do not rust. This shows that RUSTING of iron TAKES place in the presence of air and moisture both. |
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| 6555. |
Derive the relationship between Relative molecular mass and Vapour density. |
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Answer» Solution :i. The Relative Molecular Mass of a gas or vapour is the ratio between the mass of ONE molecular of the gas or vapour to mass of one atom of Hydrogen. II. Vapour DENSITY is the ratio of the mass of a certain volume of a gas or vapour, to the mass of an equal volume of hydrogen, measured under the same conditions of temperature and pressure. `"Vapour Density (V.D.)"=("Mass of a given volume of gas or vapour at S.T.P")/("Mass of same volume of hydrogen")` iii. According to Avogadro.s law, equal volumes of all gases contain equal number of molecules. Thus, let the number of molecules in one volume = n, then iv. `"V.D. at S.T.P"=("Mass of .n. molecules of a gas or vapour at S.T.P")/("Mass of .n. molecules of hydrogen")` Cancelling .n. which is common, you get `"V.D."=("Mass of 1 molecule of a gas of vapour at S.T.P.")/("Mass of 1 molecules of hydrogen")` v. SINCE hydrogen is diatomic `"V.D."=("Mass of 1 molecule of a gas or vapour at S.T.P.")/("Mass of 2 ATOMS of hydrogen")` vi. By comparing the definition of relative molecular mass and vapour density we can write as follows. `"V.D."=("Mass of 1 molecule of a gas or vapour at S.T.P.")/(2xx"Mass of 1 atom of hydrogen")` Relative molecular mass (hydrogen scale) `=("Mass of 1 molecules of a gas or vapour at STP.")/("Mass of 1 atom of hydrogen")` vii. By substitutingthe relative molecular mass value in vapour densitydefinition, we get Vapour density (V.D.)=Relative molecular mass/2 `2xx"vapour density"="Relative molecular mass of a gas"` |
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| 6556. |
Derive the relationship between Delta H and Delta U Given N_(2)(g) + 3H_(2) (g) rarr 2NH_(3) (g), Delta_(r ) H^(theta) = - 92.4 kJ mol^(-1), What is the standard enthalpy of formation of NH_(3) gas? |
| Answer» SOLUTION :`-46.2 KJ MOL^(-1)` | |
| 6557. |
Denatured spirit is obtained by mixing ethanol with………………… |
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Answer» PYRIDINE |
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| 6558. |
Deliquescent substances lose their……….. |
| Answer» SOLUTION :CRYSTALLINE SHAPE | |
| 6559. |
Deliquescent substances do not change its physical state on exposure to air. |
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Answer» |
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| 6560. |
Deliquescence is due to ..... |
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Answer» STRONG affinity to water |
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| 6563. |
Define water of crystallisation with two examples. How will you prove their existence in the examples given by you ? |
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Answer» SOLUTION :The FIXED number of water molecules present in one FORMULA unit of a SALT is water of crystalisation. The water of crystalisation in the salt is responsible for the colour and the crystal structure of the SALTS. When a coloured salt crystal is subjected to heat, it loses both its colour and crystalline structure due to loss of water. This proves their existence in salts. |
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| 6564. |
Define Volume percentage. |
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Answer» SOLUTION :Volume percentage is defined as the percentage by volume of solute (in ml) PRESENT in the GIVEN volume of the solution. Volume percentage `= ("Volume of the solute")/("Volume of the solution ")XX100` |
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| 6565. |
Define Vapour density. |
| Answer» SOLUTION :The vapour DENSITY is defined as the RATIO between the MASSES of EQUAL volumes of a gas (or vapour) and hydrogen under the same condition. | |
| 6566. |
Definevapourdensity. |
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Answer» Solution :The ratiobetweenthe massesof equalvolumesof a gasor a vapour, andhydrogen, underthesamecondition. ` V.D=(" MASSOF 1volumeof gasorgasorvapourat STP ") /(" Massof 1 VOLUMEOF hydrogen")` |
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| 6567. |
Define valency and describe its variationin a period and a group |
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Answer» Solution :Valecny of an element is its combining capacity Valency of an element=number of valence ELECTRONS (if equal to or LESS than 4) Valency of an element =8-number of valence electrons (if more than 4) |
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| 6568. |
Define : Valency |
| Answer» Solution :The VALENCY is the combining capacity of an atom of an element to acquire noble GAS CONFIGURATION. | |
| 6569. |
Define : Unsaturated carbon compounds |
| Answer» SOLUTION :Compounds of carbon which have double or triple BONDS between carbon atoms are called UNSATURATED carbon compounds. | |
| 6570. |
Define the terms 'alloy' and 'amalgam'. Name the alloy used for welding electric wires together. What are its constituents ? |
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Answer» Solution :An alloy is a homogeneous mixture of two or more metals or a metal and a non-metal, MIXED in the MOLTEN state. Amalgam is an alloy of a metal with mercury. Solder : LEAD and tin. |
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| 6571. |
Define the terms: (a) Mineral (b) Ore (c ) gangue |
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Answer» Solution :The inorganic or compound, which occurs naturally in the earth.s crust is called mineral. For example, COPPER pyrites `(CuFeS_2)` cuprite `(Cu_2O)` etc are the minerals of copper. (b) The mineral from which a metal can be exerted profitably and conveniently is called an Ore. For example,bauxite `(Al_2O_3,2H_2O) ` and clay `(Al_2O_3.2SiO_2.2H_2O)` ar the minerals of aluminium. But EXTRACTION, of aluminium is cheaper and easier from bauxite.Hence bauxite is the ore of aluminium. Thus every ore is a mineral but every mineral is not an ore. (C ) The unwanted impurities of sand and rocky materials present in the ore are known as GANGUE or matrix. We get a CONCENTRATED ore by removing the gangue present it it. |
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| 6572. |
Define theterm used in metallurgy.Roasting |
| Answer» Solution :CONVERSION of sulphide ORE of a METAL into OXIDE ore by heating is CALLED roasting. | |
| 6573. |
Define the terms : (a) mineral (b) ore and (c ) gangue. |
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Answer» Solution :(a) Mineral. The compounds of ELEMENTS occurring in earth.s crust which are associated with earthly IMPURITIES are called minerals. (b) Ore. An ore is a mineral from which METAL can be extracted conveniently and economically. ( c) GANGUE. The earthly impurities such as sand, limestone, rocks ETC. associated with minerals and ores are collectively known as gangue or matrix. |
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| 6574. |
Define theterm used in metallurgy.Calcination |
| Answer» SOLUTION :HEATING of an ore of a metal in the ABSENCE of air is called calcination. | |
| 6575. |
Define theterm used in metallurgy.Gangue |
| Answer» Solution :IMPURITY ASSOCIATED with ORES is called gangue. | |
| 6576. |
Define theterm used in metallurgy.Electrolytic reduction |
| Answer» Solution :Isolation of an ACTIVE METAL by the ELECTROLYSIS of its fused SALT is CALLED electrolytic reduction. | |
| 6577. |
Define the term Solution. |
| Answer» SOLUTION :A solution is a HOMOGENEOUS MIXTURE of TWO or more SUBSTANCES. | |
| 6578. |
Definethe term Ionic Radii. |
| Answer» Solution :IONIC RADII is definedas the distancefrom the centre of the nucleus of the ion upto the point whereit exerts its INFLUENCE on the ELECTRON cloud of the ion. | |
| 6579. |
Define the term functional group identify the functional group present in the following. i)H-overset(O)overset(||)C-Hii) H-underset(H)underset(|)overset(H)overset(|)C-overset(OH)overset(|)C=O |
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Answer» SOLUTION :It is a ATOM or group of atom or reactive part of compound which largely determine the chemical PROPERTIES of compound 1) Methanol : Alcohol (-OH) ii) ETHANOIC acid : caboxylic acid (-COOH) |
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| 6580. |
Define the term decomposition reaction. Give one example each for thermal decomposition and electrolytic decomposition reaction. |
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Answer» Solution :A chemical reaction in which a single compound or REACTANT breaks down into two or more simpler products is called chemical DECOMPOSITION reaction. Example : Decomposition reaction carried out by heating is called thermal decomposition. Decomposition of calcium CARBONATE : `CaCO_(3)(s)overset("heat")toCaO(s)+CO_(2)(g)` Example : When a decomposition reaction takes place with the help of electric current, the PROCESS is called electrolysis. Electrolytic decomposition of water : `2H_(2)O(L)overset("electric current")to2H_(2)(g)+O_(2)(g)` |
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| 6581. |
Define the term decomposition reaction . Give one example each of thermal decomposition and electrolytic decomposition. |
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Answer» Solution :In a decomposition, a single reactant breaks down into two or more simple products . When a decomposition reaction is carried out by heating , it is called thermal decomposition reaction. `underset(("Calcium carbonate"))(CaCO_(3)(s))overset ("Heat") rarr underset(("Calcium oxide"))(CAO(S))+underset(("Carbon dioxide"))(CO_(2)(g))` When a decomposition reaction is carried out with the help of electric current, the PROCESS is calledelectrolysis . `underset("Water")(2H_(2)O(1))overset("Electric current") rarr underset(("HYDROGEN gas"))(2H_(2)(g))+underset(("Oxygen gas"))(O_(2)(g))` |
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| 6582. |
Define the term alloy. Write two advantages of making alloys. |
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Answer» Solution :ADVANTAGES : (i) To protect the METAL from CORROSION. (II) To improve the quality. |
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| 6583. |
Define the rule used to identify the direction of induced current in an electric generator. How can we increase the amount of electric current produced in the electric generator? Mention the property of the current produced by AC generator. Mention an important advantage of this type of current. |
| Answer» Solution :Fleming.s right hand rule shows the direction of induced current when a conductor attached to a circuit moves in a magnetic field. The maximum POTENTIAL difference or current can be increased by increasing the RATE of rotation increasing the strength of the magnetic field increasing the number of turns on the coil. ELECTROMAGNETIC conduction is the property of the current produced by the AC generator. The major ADVANTAGE that AC electricity has over DC electricity is that AC VOLTAGES can be readily transformed to higher or lower voltage levels, while it is difficult to do that with DC voltage. Since high voltages are more efficient for sending electricity to-great distances, AC electricity has an advantage over DC. | |
| 6584. |
Define the power of lens. What is the meaning of "the power of lens is 1 dioptre" if the power of a lens -2.0D, then what type of lens is that? when an object is kept at infinity from this type of lens, what is the size of the image formed. |
| Answer» SOLUTION :The ability of a lens to converge or diverge the ray of light after REFRACTION is called power (p) of the lens. It is DEFINED as the reciprocal of the focal LENGTH i.e, `P= (1)/(f)`unit of power of a lens is diopter. A lens of focal length 100cm has a power of 1 dioptre i,e I dioptre = `1m^(-1)`If the power of a lens is 2 D then the type of lens is concave lens. The size of the image in this lens is highly diminished point sized. | |
| 6586. |
Define the ores |
| Answer» SOLUTION : Ores : The MINERALS which contain a very high percentage of a particular metal and it can be EXTRACTED PROFITABLY from them are called ores. | |
| 6587. |
Define the ore |
| Answer» Solution : ORES : The minerals which CONTAIN a very high percentage of a particular metal and it can be EXTRACTED PROFITABLY from them are CALLED ores. | |
| 6588. |
Define the minerals |
| Answer» Solution :MINERALS : The elements or COMPOUNDS, which occur NATURALLY in the earth.s crust are known as minerals. | |
| 6589. |
Define the gangue |
| Answer» SOLUTION :Gangue : Ores obtained from the earth.s crust does not contain ores of elements only, but ores are usually CONTAMINATED with large amount of impurities such as SOIL, SAND, compounds of other metals, etc., which are called gangue. | |
| 6590. |
Define the following terms. (i) Mineral (ii) ore (iii) Gangue |
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Answer» Solution :(i) Minetal: The naturally OCCURING compounds of ELEMENTS are knownas mineral. (ii) Ore: Minerals from which metal can be extracted PROFITABLY are known as Ore. (iii) Gangue: The impurities present in the ore such as sand, ROCKS etc are known asgangue. |
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| 6591. |
Define super saturated solution. |
| Answer» Solution :SUPER SATURATED solution is one that CONTAINS more SOLUTE than the saturated solution at a given TEMPERATURE. E.g. 40 g of sodium couloride in 100 g of water at `25^@ C`. | |
| 6592. |
Define : Substitution reaction |
| Answer» SOLUTION :The REACTION in which H-atoms of saturated HYDROCARBONS are displaced by another ATOM or FUNCTIONAL group is called a substitution reaction. | |
| 6593. |
Define structural isomer and draw the isomeric structures of butane. Compare the structure of benzene and cyclohexane, by drawing them. |
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Answer» Solution :Carbon compounds having same molecular FORMULA but different structural formula are called structural isomers. Example: BUTANE `(C_4H_10)` shows the following two structural isomers `H-underset(H)underset(|)overset(H)overset(|)(C )-underset(H)underset(|)overset(H)overset(|)(C )-underset(H)underset(|)overset(H)overset(|)(C )-underset(H)underset(|)overset(H)overset(|)(C )-underset(H)underset(|)overset(H)overset(|)(C )-H` n - butane `H-overset(H)overset(|)(C)-underset(H)underset(|)underset(H-C-H)underset(|)overset(H)overset(|)(C )-underset(H)underset(|)overset(H)overset(|)(C )-H` Iso-butane Structures of benzene and cyclocohexane  `{:("Benzene" C_6H_6 ,"Cyclohexane" C_6H_12),("Benzene has 6 carbon atoms","Cyclohexane has 6 carbon"),("and 6 hydrogen atoms".,"atoms and 12 hydrogen"),("Benzene has alternately","atoms. It does not consists"),("single and DOUBLE bond","of double bond between"),("between carbon atoms. It","carbon atoms".),("has three double bonds",):}`` |
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| 6594. |
Define solute and solvent. |
| Answer» SOLUTION :In a solution, the component present in lesser amount by weight is CALLED SOLUTE and the component present in a LARGE amount by weight is called solvent. | |
| 6595. |
Define saturated hydrocarbon and explain that C_2H_6is a saturated hydrocarbon. |
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Answer» Solution : A MOLECULE of saturated HYDROCARBON INVOLVES only single COVALENT BONDS. Because in `C_2H_6`all the bonds are single `H- underset(H) underset(|) overset(H) overset(|) C- underset(H) underset(|) overset(H) overset(|)C-H` |
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| 6596. |
Define : Saturated carbon compounds |
| Answer» SOLUTION :COMPOUNDS of carbon which are LINKED by only single COVALENT bonds between carbon atoms are called saturated carbon compounds. | |
| 6597. |
Define salt hydrolysis. Explain the nature of aqueous solution of CuSO_(4), on the basis of the above phenomenon |
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Answer» Solution :The phenomenon in which a salt on dissolution in WATER forms a parent acid and a parent alkali resulting in acidic, BASIC or NEUTRAL solution is called salt hydrolysis. It is the most important property of salts. `CuSO_(4)` on hydrolysis produces a strong acid that IONISES and a WEAK base that does not ionsie. This increases the concentration of `H^(+)` ions making the solution acidic with `pH lt 7` ( at `25^(@)C`) `Cu^(+2) + SO_(4)^(-1) + 2H_(2)O rarr Cu(OH)_(2) + 2H^(+) + SO_(4)^(-2)` As cation of the salt reacts with water, it is called cationic hydrolysis |
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| 6598. |
Define : Saponification reaction |
| Answer» SOLUTION :The reaction of FORMING alcohol and SODIUM salt of carboxylic acid from ESTER is known as saponification. | |
| 6599. |
Define roasting |
| Answer» Solution :The process of strongly heating SULPHIDE ores in the presence of an EXCESS of air and CONVERTING them into oxides is called ROASTING. | |
| 6600. |
Define Relative molecular mass. |
| Answer» SOLUTION :The Relative MOLECULAR mass of a molecule is the ratio between the mass of one molecule of the substance to `1//12^(th)` mass of an atom of Carbon-12 ISOTOPE. | |