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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. |
Thymine is |
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Answer» nitrogenase, cytochromes |
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| 2. |
Using the standard electrode potentials given in thepredict if the reaction between the following if feasible : (a) Fe^(3+) (a) and I^(-)(aq), (b)ag^(+)(aq)and Cu(s), (c )Fe^(3+)(aq)and Cu (s) (d) Ag(s)and Fe^(3+)(aq),(e )Br_(2)(aq)and Fe^(2+)(aq) |
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Answer» Solution :(a) The possible reaction between `Fe^(3+) (aq)` and `I^(-)(aq)` is `2Fe^(3+)(aq)+2I^(-)(aq)rarr2Fe^(2+)(aq)+I_(2)(s)` The above redox reaction can be split into the following two half reaction one involving oxidation and the other redcution wiritng electrode potential for each half RECTION from OVERALL reaction `2Fe^(3+)(aq) +2I^(-)(aq)rarr2Fe^(2+)+I_(2)(s)` since the EMF for the above reaction `Ag^(+)` (aq) and Cu (s) is `Cu(s)+2Ag^(+)(aq)rarrCu^(2+)(aq)+2ag(s)` The above redox reaction can be split into the following two half reaction writing electrode potential for each half reaction form we have oxidation`Cu(s)rarrCu^(2)(aq)+2e^(-), E^(@)=-0.34 V` Reduction `Ag^(+)(aq)+E^(-)rarrAg(s)xx2, E^(@)=+0.80 V` overall reaction `Cu(s)+2Ag^(+)(aq)rarrCu^(2+) (aq)+2 (s),E^(@)=+0.46V` since the EMF of the above reaction comes out to be postive therefore the above reaction is feasible (c ) suppose the reaction between `Fe^(3+)(aq)rarr Cu^(aq)+2Ag(s),E^(@)=+0.46 V` since the EMF of the above reaction comes oiut to be postive therefore to the following equatin `Cu(s)+2Fe^(3+)(a)rarr3Cu(aq)+2Fe^(2+)(aq)` the above reaction can be split into the following two half reaction wirting elecrode potential for each half reaction from we have oxidation `Cu(s)rarrCu^(2+)(aq)+2e^(-) , E^(@)=-0.34 V` Reduction `Fe^(3+)(aq)+E^(-)rarrFe^(2+)(aq)xx2 , E^(2)=+0.77V` overall reaction `Cu(s)_+2Fe^(3+)(aq)rarrCu^(2+)+2Fe^(2+)(aq),E^(@)=+0.43 V` since the EMF of the reaction is postive therefore the above reaction is feasible alternatively if the raction between 1 `Fe^(3+)` (aQ) and Cu (s) occurs according to the followng equation The EMF of the reaction comes out to be -ve -0.36 V(-0.34 V -0.034 V)and hence this rection is not feasible (d) suppose the reaction between Ag(s) and`Fe^(3+)` (Aq) occurs accoding to the following eqation The above reaction can be split intothe following two half rection writing electrode potential for each half reaction from we have oxidation `Ag(s)rarrAg^(+)(aq)+e^(-), E^(@)=-0.80 V` Reduction `Fe^(3+)(aq)+E^(-)rarrFe^(2+)(aq), E^(@)=+0.77 V` since the EMF of the reaction is negative therefore the above reaction is not feasible Alternatively the rection between Ag (s) and `Fe^(3+)` (aQ) MAY occur according to the following equation `3Ag(s)+Fe^(3+)(aq)rarr3Ag^(+)(aq)+Fe(s)` on similar lines we can calcualte the EMF of this reaction comes to be even followng equation `Br_(2)(aq)+2Fe^(2+)(aq)rarr2Br^(-)(aq)+2Fe^(2+)(aq)` the above reaction can be split in to the followng two half rection writing electrode potential for each half reaction from the we have oxidation `Fe^(2+)(aq)rarrFe^(3+)(aq)+e^(-)xx2,E^(@)=-0.77 V` Reduction : `Br_(2)(aq)+2e^(-)rarrBr^(-)rarr2Br^(-)(aq),E^(@)=+1.09 V` overall reaction `2Fe^(2+)(aq)+Br_(2)(aq)rarr2Fe^(3+)(aq)+2 Br^(-)(aq)'E^(@)=+0.32 V` since the EMF for the above reaction is positive therefore this reaction is feasible |
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| 3. |
Write a note about gas hydrates. |
| Answer» Solution :Gas hydrates are a KIND of inclusion compounds where gas molecules are trapped in the crystal lattice having voids of RIGHT SIZE, without being chemically bonded. An intevesting hydrate is the of The HYDRONIUM ion `(H_3O)` in the gas phase. Similar to methane hydrate. Each water MOLECULE is bonded to three other in the dodecahedron. | |
| 4. |
Which one of the following is manufactured in Haber's process? |
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Answer» `SO_(3)` |
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| 5. |
What is the range of frequencles used in a microwave oven ? |
| Answer» SOLUTION :The microwaves have approximately a frequency RANGE of `3xx 10^(10) " to " 3 XX 10^(12)HZ` | |
| 6. |
Write preparation of Hydrogen peroxide. |
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Answer» Solution :(i) Acidifying barium peroxide and removing excess water by EVAPORATION under reduced PRESSURE gives hydrogen peroxide. `BaO_2. 8H_2O_((s)) + H_2SO_(4(aq)) to BaSO_(4(s)) + H_2O_(2(aq)) + 8H_2O_((l))` (ii) Peroxodisulphate, obtained by electrolytic oxidation of acidified sulphate SOLUTIONS at high current density, on hydrolysis yields hydrogen peroxide. `2HSO_(4(aq))^(-) overset"Electrolysis"to HO_3SOOSO_3H_((aq)) overset"Hydrolysis"to 2HSO_(4(aq))^(-) + 2H_((aq))^(+) + H_2O_(2(aq))` This METHOD is now used for the laboratory preparation of `D_2O_2` . `K_2S_2O_(8(s)) + 2D_2O_((l)) to 2KDSO_(4(aq)) + D_2O_(2(l))` (iii)Industrially it is prepared by the auto-oxidation of 2-alklylanthraquinols. (2-ethyl anthraquinol) `O_2"(air)"to H_2O_2`+ (Oxidised product.) In this case 1% `H_2O_2` is formed. It is extracted with water and concentrated to ~30% (by mass) by distillation under reduced pressure. It can be further concentrated to ~85% by careful distillation under low pressure. The remaining water can be frozen out to obtain pure `H_2O_2`. |
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| 7. |
Which of the following represents schrodinger equations |
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Answer» `(del^2/(delx^2)+del^2/(dely^2)+del^2/(delz^2))PSI=(8pi^2m)/h^2[E-V]Psi=0` |
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| 8. |
Which of the following will not displace hydrogen? |
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Answer» Ba |
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| 9. |
Which of the following is most reactive in its reaction with C_(2)H_(4)? |
| Answer» Answer :A | |
| 10. |
The standard enthalpiesof combustion of C_(6)H_(6) (l),C ( graphite) andH_(2)(g) are respectively -3270 kJ mol^(-1), - 394kJ mol^(-1) and-286 kJmol^(-1) . What is the standard enthalpy of formation ofC_(6)H_(6)(l)in kJ mol^(-1) / |
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Answer» `- 48` (ii) `C+ O_(2) rarr CO_(2), DeltaH = -394kJ mol^(-1)` (iii) `H_(2)+(1)/(2) O_(2) rarr H_(2)O,DetlaH=-286kJ mol^(-1)` AIM `: 6C+ 3H_(2) rarrC_(6)H_(6) , DeltaH=?` `6 XX`Eqn. (ii) `+ 3 xx ` Eqn. (iii) -Eqn. (i) ,gives required eqn.with `DeltaH =+ 48 kJ mol^(-1)` |
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| 11. |
The SI units of the coefficient of viscosity is ………………………….. . |
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Answer» |
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| 12. |
Which one of the following molecular hydrides acts as a Lewis acid |
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Answer» `NH_(3)` |
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| 13. |
Which one of the following represents 180g of water ? |
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Answer» 5 Moles of water |
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| 14. |
Why a person suffering from high blood pressure is advised to take minimum quantity of common salt ? |
| Answer» Solution :Osmotic pressure is directly proportional to the conecntration of SOLUTES our body FLUIDS contains a NUMBER of solutes. On large amount of salt ions entering into the body fluids therby raises the concentration of solute .As a result , osmotic pressure increase which may RUPTURE the bloodcells. | |
| 15. |
What is the hybridisation state of benzyl carbonium ion ? |
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Answer» `SP^(2)` |
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| 16. |
Which of the following substance is in liquid form at room temperature ? |
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Answer» Methane |
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| 17. |
Which of the following reaction is incorrect according to thermodynamics ? |
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Answer» `DELTA G^(@) = - nFE^(@)` |
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| 18. |
The wrong statement among the following regarding alkali metal halides is |
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Answer» `Deltaf H^(0)` values becomes less negative from LITHIUM to caesium |
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| 19. |
Which among the following alkenes on reductive ozonolysis produces only propanone |
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Answer» 2-methylpropene |
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| 20. |
Which of the following do not respond to flame test |
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Answer» Be |
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| 21. |
Which of the following acids (given below) react with NaHCO_(3) and liberate Co_(2)(g) ? |
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Answer» |
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| 22. |
What happens when the concentration of H_(2) and I_(2) are increased in the reaction H_(2)+I_(2)hArr2HI ? |
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Answer» Solution :According to Le Chatelier's principle, the effect of increases in concentration of a substance is to SHIFT the equilibrium in a direction that consumes the added substance. Let us consider the REACTION `H_(2)(G)+I_(2)(g)hArr2HI(g)` The addition of `H_(2)` or `I_(2)` to the equilibrium mixture disturbs the equilibrium. In order to minimize the stress, the system shifts the reaction in a direction where `H_(2)` and `I_(2)` are consumed i.e., the formation of additional HI would balance the effect of added reactant. Hence, the equilibrium SHIS to the right (forward direction) i.e. the forward reaction takes place until the equilibrium is re-established. Similarly, REMOVAL of HI (product) also favours the forward reaction. |
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| 23. |
Which among the following is correct about gamma-rays ? |
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Answer» HIGH ENERGY electrons |
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| 25. |
There are three isotopes of hydrogen and three naturally occuring isotopes of oxygen (""^(16)O, ""^(17)O and ""^(18)O). How many kinds of water molecules are possible . Write their formulae. |
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Answer» SOLUTION :18 . Their formulae are : `H-""^(16)O-H, H-""^(17)O-H, H-""^(18)O-H, H-""^(16)O-D, H-""^(17)O-D,H-""^(18)O-D,H-""^(16)O-T,H-""^(17)O-T,H-""^(18)O-T, D-""^(16)O-D,D-""^(17)O-D,D-""^(18)O-D,T-""^(16)O-D,T-""^(17)O-D,T-""^(18)O-D,T-""^(16)O-T,T-""^(17)O-T,T-""^(18)O-T` However, most abundant HEAVY water occuring in ordinary water is DEUTERIUM oxide, i.e., `D-""^(16)O-D`. |
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| 26. |
Zn salt is mixed with (NH_(4))_(2)S of molarity 0.021M. What amount of Zn^(2+) will remain unprecipitated in 12 mL of the solution ? (K_(SP) "of ZxnS" = 4.51xx10^(-24)) |
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Answer» |
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| 28. |
The stability of dihalides of Si, Ge, Sn and Pbincreases steadily in the sequence |
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Answer» `PbX_(2) LT lt SnX_(2)lt lt GeX_(2) lt lt SiX_(2)` |
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| 29. |
Which of the following halogens has great affinity for hydrogen? |
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Answer» F |
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| 30. |
The temperature of K at which DeltaG =0 for a given reaction with DeltaH= -20.5 kJ mol^(-1)and DeltaS =- 50.0 JK^(-1)mol^(-1) |
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Answer» `-410 ` |
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| 31. |
Which one is usedas free radical initiator in polymerisation reaction ? |
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Answer» ethylene |
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| 32. |
What is the wavelength for the electron accelerated by 1.0xx10^(4) volts? |
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Answer» Solution :Step I.Calculation of the velocity of elctron ENERGY (kinetic energy)of eectron`=1.0xx10^(4)`volts. `=1.0xx10^(4)xx1.6xx10^(-19)J=1.6xx10^(-15)J` `=1.6xx10^(-15)kgm^(2)s^(-2)` or`(1)//(2) mv^(2)=1.6xx10^(-15)kgm^(2)s^(-2)` or`v=9((2xx1.6xx10^(-15)kgm^(2)s^(-2))/(9.1xx10^(-31)kg))^(1//2)=5.93xx10^(7)MS^(-1)` Step II. Calculation of WAVELENGTH of the electron According to de Broglie equation, `gamma=h/(mv),gamma=((6..626xx10^(-34)kgm^(2)s^(-1)))/((9.1xx10^(-31)kg)xx(5.93xx10^(7)ms^(-1)))=1.22xx10^(-11)m` |
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| 33. |
Which colour is shown by Rubidium salts on flame test? |
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Answer» RED violet |
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| 34. |
When pottassium permanganate acts as oxidising agent it is converted into MnO_(4)^(-2),Mn_(2)O_(3),MnO_(2)andMn^(+2) then calculate change in electrons. |
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Answer» 4, 3, 1, 5 |
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| 35. |
Which process of purification is represented by the following equation underset("Impure")Ti+2I_(2) overset(250^(@)C)to Til_(4)overset(1400^(@)C)to underset("pure")Ti+2I_(2) |
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Answer» Cupellation |
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| 36. |
Which one of the following is the correct statement for respiration in humans? |
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Answer» Boric acid is a protonic acid |
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| 37. |
What is the meaning of the boiling point of water is 100^@C ? |
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Answer» Solution :In close vessel at `100^@C` temperature the vapour PRESSURE of water is ATMOSPHERE (1.013 BAR) and the equilibrium is ESTABLISHED between water and its vapour. `H_2O_((l)) hArr H_2O_((g))`….(`100^@C` + 1.013 bar) |
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| 38. |
Which one is biofertilizers ? |
| Answer» Solution :Both (A) and (B) | |
| 39. |
Which of the following has activation effect on benzene ring ? -OH, -COCH_(3), -NO_(2), -NH_(2), -Cl, -Br, -NHCOCH_(3), -COOH |
| Answer» Solution :Activator groups : -OH, `-NH_(2), -NHCOCH_(3)` | |
| 40. |
What is [Ag^(+)] ina solution made by dissolving both Ag_(2)CrO_(4) and Ag_(2)C_(2)O_(4) untilsaturation is reachedwith respect to both salt ? [K_(sp) = (Ag_(2)C_(2)O_(4)) = 2 xx 10^(-11), K_(sp) (Ag_(2)CrO_(4)) = 2 xx 10^(-12)] |
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Answer» `2.80 xx 10^(-4)` `Ag_(2)C_(2)underset(2y+2x)(O_(4)(s))hArr2Ag^(+)underset(y)((aq.))+C_(2)O_(4)^(2-)(aq.)` `(K_(sp_(1)))/(K_(sp_(1))) = x/y = (2XX10^(-12))/(2 xx 10^(-11)) rArr = 0.1 ` `2 xx 10^(-11) = (2 x + 2y)^(2).y` `2 xx 10^(-11) = 4.84y^(3)` `y = 1.6 xx 10^(-4)` `:. x = 0.16 xx 10^(-4)` TOTAL`[Ag^(+)] = 2 x + 2y` `= (2 xx 0.16 + 2 xx 1.6) xx 10^(-4) = 3.52 xx 10^(-4)` |
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| 41. |
Which electron displacement effect explain the following correct orders of acidity of the carboxylic acids? |
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Answer» Solution :`CH_(3)CH_(2)COOH gt (CH_(3))_(2)CHCOOH gt (CH_(3))_(3) CCOOH` As the number of alkyl group increases, `+I` effect increase and it STRENGTHEN the `O-H` bond. i.e., `O-H` bond dissociation is very difficult.  Therefore `+I` effect explain the correct ORDERS of ACIDITY of the CARBOXYLIC ACIDS. |
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| 42. |
Which one of the following species has tendency to show -I effect? |
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Answer» `-CH_(3)` |
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| 43. |
Which one of the following species has tendency to show +I effect? |
| Answer» Answer :D | |
| 44. |
Which of the following change requires a reducing agent |
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Answer» `CrO_(4)^(2-)RARR Cr_(2)O_(7)^(2-)` |
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| 45. |
What will be value of Delta G^(@) for ice at 298 K temperature? |
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Answer» `-ve` |
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| 47. |
When NiO is doped with a small quantity of Li_(2)O |
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Answer» both CATION and ANION VACANCIES are generated |
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| 48. |
What is the mass of the precipitate formed when 50 mL of 16.9 % solution of AgNO_(3) is mixed with 50 mL of 5.8 % NaCl solution ? (Ag = 107.8,N=14,O=16,Na=23,Cl=35.5) |
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Answer» 3.5 g |
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| 49. |
Which one of the following is not present in trposphere ? |
| Answer» Solution :`N_(2)O_(2)` | |
