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This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
How manay millimoles of potassium dichromate is required to oxidise 24 ml o f0.5 M Moher salt solution in acidic medium ? |
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Answer» The balanced chemical EQAUTION for the redox reaction is `K_(2)Cr_(2)O_(7)+6(NH_(4))SO_(4).FeSO_(4).6H_(2)O+7H_(2)SO_(4)rarrK_(2)SO_(4)+6(NH_(4))SO_(4)+3Fe_(2)(SO_(4))_(3)+Cr_(2)(SO_(4))_(3)+43H_(2)O` From the balanced eqaution 6 moles Mohr salt are oxidised by `K_(2)Cr_(2)O_(7)` =1 MOLE `therefore` 12 millimoles of Mohr 's salt will be oxidised by `K_(2)Cr_(2)O_(7)=(1)/(6)xx12=2` millimoles |
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| 2. |
How manay grams of K_(2)Cr_(2)O_(7) are required ot oxidise Fe^(2+) present in 15.2 g ofFeSO_(4) to Fe^(3+) if the reaction is carried out in an acidic medium ? |
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Answer» `K_(2)Cr_(2)O_(7)+6FeSO_(4)+7H_(2)SO_(45)rarrK_(2)SO_(4)+Cr_(2)(SO_(4))_(3)+7H_(2)` From the balanced equation it is clear that 6 Moles of `FeSO_(4)=1 "Mole of" K_(2)Cr_(2)O_(7) or 6xx152 g"for" FeSO_(4)` are oxidised by `K_(2)Cr_(2)O_(7)=294` g 152 g of `FeSO_(4)` are oxidised by `K_(2)Cr_(2)O_(7)=(294)/(6xx152)xx15.2=4.9 g` |
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| 3. |
How m any orbitals are a sso cia ted w ith n = 4 ? |
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Answer» 16 |
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| 5. |
How m any number of proton, electron and neutron n in .^(55)Mn^(+2) respectively ? |
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Answer» 25,27,30 No. of PROTONS = 25 No. of ELECTRONS = 25 - 2 = 23 No. of neutrons = 25 - 25 = 30 |
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| 6. |
How long would it take a radiowave of frequency, 6 xx 10^(3) sec^(-1) to travel from Mars to the Earth, a distance of 8 xx 10^(7) km? |
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Answer» Distance to be travelled from Mars to the EARTH `= 8 xx 10^(7) km = 8 xx 10^(7) xx 10^(3) m (1 km = 10^(3) m)` `:.` Time taken `= (8 xx 10^(7) xx 10^(3))/(3 xx 10^(8)) = 2.66 xx 10^(2) SEC = 4` min 26 sec |
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| 7. |
How it is decide the hybridization of atom is sp ,sp^(2) " or " sp^(3) ? |
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Answer» SOLUTION :It is DECIDE on the base of bond angle and shape Bond angel - `180^(@)` LINEAR shape, So, sp hybridization. Bond angel - `120^(@)` shape, So, `sp^(2)`- hybridization. Bond angel - `109.5^(@)` shape, So, `sp^(3)` hybridization. |
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| 8. |
How is wave number and wavelength of a wave related? |
| Answer» SOLUTION :`BARV=1/(LAMDA)barv=`WAVE NUMBER, `lamda`= wave length | |
| 9. |
How is velocity is related with wave number and frequency ? |
| Answer» Solution :`C = nlamda` (or) `v = c/(lamda)` where c = VELOCITY, v = FREQUENCY, `lamda`= WAVELENGTH | |
| 10. |
How is vanaspati ghee prepared from edible oils ? |
| Answer» Solution :Vanaspati is a fully or PARTIALLY hydrogenated vegetable COOKING oil, often used as a cheaper substitute for ghee and butter.Hydrogenation is performed using a CATALYST known as "SUPPORTED nickel catalyst", in REACTORS at low-medium pressure (3-10 bar). | |
| 11. |
How is Tritium prepared? |
Answer» Solution :It OCCURS naturally as a result of nuclear reactions induced by COSMIC RAYS in !he UPPER atmosphere 
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| 12. |
How is the use of insecticides like DDT and BHC harmful to the plants and the soil? |
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Answer» Solution :(i) They are absorbed by the SOIL and contaminate root CROPS like radish, carrot etc. (ii) Their repeated use produces a RESISTANCE in the pests and hence they BECOME INEFFECTIVE |
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| 13. |
Howis thesolutionof Schrodingerequationfor multielectronatom ? |
| Answer» SOLUTION :APPLICATIONOF Schrodingerequationto themultielectronatomspresentsa DIFFICULTY .Thisdiffcultycan beovercome byusingapproximatemethod. | |
| 14. |
How is the SI system ? OR Properties of SI system are ......... |
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Answer» UNIFORM |
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| 15. |
How is the sequence of energy levels of molecular orbitals written in case of heavier diatomic molecules? |
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Answer» Solution :For heavier DIATOMIC molecules , the ORDER of energy levels of `sigma_(2)p_(z) , pi_(2)p_(X), pi_(2)p_(y)` is reversed , (i.e.) `sigma_(2)p_(z)` has lesser energy than `pi_(2)p_(x)` and `pi_(2)p_(y)`. HENCE , the order of increasing energies of Mos is , `sigma_(1S) lt sigma_(as)^(**) lt sigma_(2s) lt sigma_(2s)^(**) lt sigma_(2)p_(z) lt pi_(2)p_(x) = pi_(2)p_(y) lt pi_(2)^(**) p_(x) = pi_(2)^(**)p_(y) lt sigma_(2)p_(z)`. |
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| 16. |
How is the pure liquid is separated from two mixture obtained by vapour distillation? |
| Answer» SOLUTION :By SEPARATING FUNNEL | |
| 17. |
How is the partial pressure of a gas in a mixture related to the total pressure of the gaseous mixture ? |
| Answer» SOLUTION :PARTIAL PRESSURE of a gas =Mole FRACTION of that gas xxTotal pressure. | |
| 18. |
How is the nature of covalent bond between two atoms predicted ? |
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Answer» Solution :Nature of the COVALENT bond between two ATOM is PREDICTED based on the DIFFERENCE in electronegativiy. If there is no difference in the electronegativity of bonded atom, the bond is PURE covalent. If electronegativity difference arises between bonded atoms, the bond is polar covalent. |
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| 19. |
How is the name given to the elements whose atomic number is more than 100 ? |
| Answer» SOLUTION :The ROOTS are put TOGETHER in order of digits which MAKE up the atomic number and "ium" is added at the END. The IUPAC names for elements with Z above 100. | |
| 20. |
How is the mass of an element related to the number of atoms present in it ? |
| Answer» Solution :The MASS of `6.022 xx 10^23` atoms of a GIVEN ELEMENT is EQUAL to its gram atomic mass. | |
| 21. |
How is the magnetic moment of paramagnetic species is related to the number of unpaired electrons present in it? |
| Answer» SOLUTION :MAGNETIC MOMENT `mu=sqrt(n(n+2)BM)` where n is the number of unpaired electrons. | |
| 22. |
How is theenthalpy of vaporization of a substance relateed to its enthalpy of fusion? |
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Answer» The enthalpyof vaprization is GREATER than the enthalpy of fusion. |
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| 23. |
How is the bond order related to strength of the bond ? |
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Answer» Solution :BOND ORDER a Bond strength . HIGHER the bond order for a MOLECULE, higher is the strength of the bond . |
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| 24. |
How is the angularnode in s,p,d,f |
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Answer» Solution :Angular node : L For sorbitals= 0 `:.` zeronode p ORBITALS `l =1 :.` noenode F orbital l=3`:.`THREE node |
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| 25. |
How is sulphur detected using the Sodium fusion extract of the given organic compound? |
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Answer» Solution :Te sodium FUSION EXTRACT is acidified with ACETIC and lead acetate. A BLACK precipitate of lead SULPHITE is formed which indicates the presence of sulphur. `overset(2-)(S)+overset(2+)(Pb)-underset("black ppt")(PbS)` |
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| 26. |
How is sulphur detected using sodium fusion extract of given organic compound? |
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Answer» Solution :Test`""` OBSERVATION`""` Inference SFE+Lead Acetate+Acetic Acid`""` BLACK PPT`""` SULPHUR is PRESENT |
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| 27. |
How is pyrophosphoric acid related to orthophosphoric acid ? |
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Answer» SOLUTION :Pyrophosphoric acid `(H_(4)P_(2)O_(7))` is the ANHYDRIDE of orthophosphooric acid and is obtained by removal of a molecule of `H_(2)O` from two molecules of `H_(3)PO_(4)`. For structures, refer to PAGE 11//137. `underset("Orthophophoric acid")(2H_(3)PO_(4))overset(523 K)tounderset("Pyrophosphoric acid")(H_(4)P_(2)O_(7))+H_(2)O` |
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| 28. |
How is propyne prepared from an alkyene dihalide ? |
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Answer» Solution :`CH_(3)-CH_(2)- underset(CI) underset(|)overset( CI) overset( |) (C ) -Hoverset( ALC. KOH) (to)CH_(3) - CH = underset( CI )underset(|) (C ) - H + HCI` (1,1,- dichloroprpane )(1- Chloroprop -1- ene ) `CH_(3)- C = CH` (propyne ) |
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| 29. |
How is propene obtained from propyl chloride? |
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Answer» Solution :When proply chloride is HEATED with ALCOHOLIC potash, PROPENE is obtained. `CH_(3) - CH_(2)CH_(2)Cl + KOH_((abc)) overset(""Delta"")(rarr) CH_(3) - underset("propene")(CII) = CH_(2) + KCl + H_(2)O` |
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| 30. |
How is plaster of paris prepared ? |
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Answer» Solution :Plaster of PARISE is a HEMIHYDRATE of calcium sulphate `CaSO_(4^(*))1//2H_(2) O` . It is OBTAINED by HEATING gypsumat 393 K `underset("Gypsum")(2CaSO_(4^(*))2H_(2))O_((s))overset(Delta)tounderset("Plaster of paris")(2CaSO_(4^(*))H_(2)O)+3H_(2)O` |
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| 31. |
How is phosphorus estimated in an organic compound ? |
| Answer» SOLUTION :EITHER as AMMONIUM phosphomolybdate or as MAGNESIUM PYROPHOSPHATE. | |
| 32. |
How is phenolphthalein used to distinguish between sodium carbonate and sodium bicarbonate. |
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Answer» Solution :Sodium carbonate is more soluble and furnishes two moles of hydroxyl ions PER mole. Sodium bicarbonate is less soluble and furnishes one mole of hydroxyl ions per mole. AQUEOUS sodium carbonate solution is basic and phenolphthalein is PINK . Aqueous bicarbonate is also basic, but `[OH^(-)]` is not sufficient to give pink colour with phenolphthalein. |
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| 33. |
How is ozone produced in stratosphere ? |
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Answer» Solution :Ozone in stratosphere is product of action of UV-radiations on dioxygen `(O_2)` molecules. The UV radiation split APART molecular oxygen into free oxygen ATOMS. These oxygen atoms combine with the molecular oxygen to from ozone. `O_(2(g)) underset("UV-radiation")OVERSET(hv)to O + O` `O_(2(g)) + O_((g)) underset("radiations")overset(hv)hArr O_3` Note: In stratosphere, a photon with a WAVELENGTH between 180 nm and 240 nm breaks. the `O_2` molecule into atomic oxygen. |
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| 34. |
How is Ozone layer formed in the stratosphere? Name a chief chemical that causes its depletion. |
| Answer» Solution :Ozone LAYER is formed due to ACTION of uv radiation on OXYGEN. CFC or FREONS. | |
| 35. |
How is nitrogen prepared from ammonia? |
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Answer» Solution :`NH_(3)` is first treated with dil. HCl and the ammonium chlorids thus formed is treated with an aqueous solution of sodium NITRITE when `N_(2)` gas is evolved. `NH_(3)(g)+HCl(aq)toNH_(4)Cl(aq)` `NH_(4)Cl(g)+NaNO_(2)(aq)toNH_(4)NO_(2)(aq)+NaCl(aq)` `NH_(4)NO_(2)(aq)OVERSET(Delta)toN_(2)(g)+2H_(2)O(l)` |
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| 36. |
How is nitrogen in the laboratort ? Write the chemical equations of the reactions involved. |
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Answer» Solution :Nitrogen is prepared in the laboratory by heating an EQUIMOLAR AQUEOUS solution of AMMONIUM chloride and sodium nitrite. The ammonium nitrite formed as a result of double decomposition reaction, being unstable decomposes to form dinitrogen gas. `NH_(4)Cl(aq)+NaNO_(2)(aq)toNH_(4)NO_(2)(aq)+NaCl(aq)` `underset("Amm.nitrite")(NH_(4)NO_(2)(aq))OVERSET("Heat")tounderset("Dinitrogen")(N_(2)(G)+2H_(2)O(l)` |
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| 37. |
How is molecular formula different from the empirical formula? |
| Answer» Solution :Emprical formula of a compound is defined as the SIMPLEST formula that GIVES the ratio of atoms of various elements in a MOLECULE. e.g., Empirical formula of BENZENE is CH. | |
| 38. |
How is methanol synthesized from hydrogen? Give the uses of methanol. |
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Answer» Solution :(i) HUGE quantities of hydrogen are used for the synthesis of methanol from carbon monoxide in presence of copper catalyst. `CO_((g))+2H_(2(g))toCH_(3)OH_((1))` (II) Methanol is an industrial solvent and a starting material for the manufacture of formaldehyde used in making plastics. |
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| 39. |
How is Methane prepared from sodium acetate? |
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Answer» Solution :Decarboxylation: When SODIUM SALT of carboxylic acid is heated with soda lime (mxiture of sodium hydroxide and calcium oxide), an alkane containing one CARBON atom less than parnet carboxylic acid is formed. This REACTION is called decarboxylation. `underset("sodium ethnoate")(CH_(3)COONa)+NaOHunderset("Heat")overset(CaO)(to) underset("methane")(CH_(4)+Na_(2)CO_(3)` |
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| 40. |
How is liquid -vapour equilibrium exist ? |
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Answer» Solution :LIQUID WATER is in equilibrium with vapour at 373 K and 1 ATM pressure in a closed VESSEL `H_(2)O(l) hArr H_(2)O(G)` (ii) Rate of evaporation = Rate of condensation |
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| 41. |
How is iodoethane converted to ethane ? |
| Answer» Solution :`UNDERSET("Iodoethane")(CH_(3) CH_2I) + HI overset("RED P") underset(Delta)(to) Cunderset("Ethane") (H_(3) - CH_(3)) + I_(2)` | |
| 42. |
How is inorganicbenzene prepared? |
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Answer» Solution :Borazineis calle inorganic benzene. It is prepared by HEATING the addition compounds of diborane with ammonia to `473K` . `3B_(2)H_(6) + 6NH_(3) overset(" LOW comp. ")rarr underset( "Addition compound ")(3[BH_(2)(NH_(3))_(2)]^(+) [BH_(4)]^(-)) overset(473 K)rarrunderset("Borazine")(2B_(3)N_(3)H_(6)) +12 H_(2)` For structureof borazine. |
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| 43. |
How is hydrogen used in metallurgy? Prove it with an example. |
| Answer» Solution :In metallurgy, for the extraction of PURE metals from their mineral SOURCES, hydrogen is ne reduce many METAL oxides to metals at HIGH TEMPERATURES. `CuO_((s))+H_(2(g))toCu_((s))+H_(2)O_((g))` | |
| 44. |
How is hydrogen peroxide prepared on industrial scale? |
Answer» SOLUTION :On an industrial scale, HYDROGEN PEROXIDE is prepared by AUTO oxidation of of 2-alkyl anthraquinone.
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| 45. |
How is hydrogen peroxide prepared industrially ? Explain why it is stored in coloured wax-lined glass or plasticbottles ? |
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Answer» Solution :Industrially, `H_(2)O_(2)` is perpared by the auto oxidation of 2-ethylanthraquionol to 2-ethylanthraquinone. `H_(2)O_(2)` is STORED in wax-lined glass or PLASTIC bottles so that it does not decompose into `H_(2)OandO_(2).` Because it is decomposed to `H_(2)OandO_(2)` when COMES in contact with sunlight. |
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| 46. |
How is hydrogen peroxide is used to restore the white colour of old paintings. |
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Answer» SOLUTION :Hydrogen peroxide is used to restore the white colour which was lost due to the reaction of hydrogen sulphide in air with the white PIGMENT `Pb_(3)(OH)_(2)(CO_(3))_(2)` to form black COLORED lead sulphide (PBS). Hydrogen peroxide oxidises black coloured lead sulphide to white coloured lead sulphate, there by restoring the colour. `Pbs+4H_(2)O_(2)toPbSO_(4)+4H_(2)O` |
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| 47. |
How is hydrogen peroxide labelled as a green chemical ? |
| Answer» SOLUTION :Now-a-days, hydrogen peroxide is used in green chemistry. It is used as a harmless bleaching agent. It is used in environmental treatment of domestic and industrial effluents and restoration of aerobic CONDITIONS to sewage WASTES. Hydrogen peroxide is ALSO used in the oxidation of pollutant CYANIDES. | |
| 48. |
Identify the bond between H and F in HF molecule. |
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Answer» Solution :lectronic configuration of hydrogen atom is `1_(s)^(1)`. Valence shell electronic configuration of fluorine atom is `2s^(2)" "2p_(x)^(2)" "2p_(y)^(2)" "2p_(Z)^(1)` When half iled 1ls orbital of hydrogèn LINEARLY overlaps with a half filled `2p_(z)` orbital of fluorine, a `sigma` COVALENT BOND is formed between hydrogen and fluorine. 
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| 49. |
How is heavy water produced from ordinary water ? |
| Answer» SOLUTION :It is OBTAINED by prolongled ELECTROLYSIS of ordinary water containing 3% NaOH. | |
| 50. |
How is heavy hydrogen manufactured ? |
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Answer» Solution :It is manufactured by the electrolysis of HEAVY water containing a little of `H_(2)SO_(4)`or `NaOH` to make it a good conductor of electricity . `UNDERSET("Heavy water")(2D_(2)O(l)) overset("Electrolysis")to underset(("At cathode"))(2D_(2)(G))+ underset(("At ANODE"))(O_(2)(g))` In the laboratory , it can be prepared by the action of heavy water on sodium metal. `2D_(2)O(l) + 2Na(s)to 2NaOD (aq) + D_(2)(g)` |
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