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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. |
Symbol._(35)^(79)Br and._(35)^(79) Br canbe writtenwhereassymbols ._(79)^(35)Br andarenotacceptableAnswerBriefly . |
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Answer» SOLUTION :In `._(35)^(79) BR` atomicnumberis at the leftlowerportionatomicmass is at upperside. HENCE itacceptable `._(79)^(35) Br`is notaccepta blebecausemass and atomicnumberare notat properposition . `.^(35)Bt`is notacceptablebecauseit showsonlyatomicnumberatomicmass is NOTMENTION. |
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| 2. |
Suspension of slaked lime in water is known as |
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Answer» lime water White suspension is CALLED milk of lime and it is used for white WASHING. |
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| 3. |
Suspension of ...... in water is known as milk of magnesia. |
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Answer» `MgCl_(2)` |
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| 4. |
The suspension of slaked lime in water is known as |
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Answer» LIME WATER |
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| 5. |
surfactant molecules form micelles in aqueous solution, which: |
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Answer» tend to congregate due to their HYDROPHOBIC tails |
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| 6. |
Surface tension vanishes at |
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Answer» BOILING POINT |
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| 7. |
Surface water contains |
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Answer» Salt+Organic matter |
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| 8. |
Surface tension of water is 73 dyne cm^(-1) at 20^(@)C. If surface area is increased by 0.10" m"^(2), work done will be |
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Answer» 73 ergs `=73" dyne "CM^(-1)xx0.1" m"^(2)` `=73" dynwe "cm^(-1)xx0.1xx10^(4)"ergs"` `=7.3xx10^(4)" dyne " cm=7.3xx10^(4)" ergs"` |
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| 9. |
Surface tension of a liquid is a molecular phenomenon of liquids involving the force of cohension along the liquid molecules. It is scalar quantity and is numberically equal to the surface energy. Numerically, it is proved that the potential soluble salts and surfce active substance. Sparingly soluble salts and surface acitve substances decrease the surface tension of the liquid. However, the fairly soluble solutes increase the surface tension of the liquid. Surfacetension of a liquid is independent of surface area but it depends on the intemolecular forces and the temperature. Whenoil is placed on the surface of hot water, formation of droplets takes place because : |
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Answer» surface tension not hot WATER = surface tension of oil |
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| 10. |
Surface tension of lyophillic sols is |
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Answer» lower than that of `H_(2)O` |
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| 11. |
Surface tension of a liquid is a molecular phenomenon of liquids involving the force of cohension along the liquid molecules. It is scalar quantity and is numberically equal to the surface energy. Numerically, it is proved that the potential soluble salts and surfce active substance. Sparingly soluble salts and surface acitve substances decrease the surface tension of the liquid. However, the fairly soluble solutes increase the surface tension of the liquid. Surfacetension of a liquid is independent of surface area but it depends on the intemolecular forces and the temperature. Which of the following has the highest surface tension ? |
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Answer» Water |
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| 12. |
Surface tension of a liquid is a molecular phenomenon of liquids involving the force of cohension along the liquid molecules. It is scalar quantity and is numberically equal to the surface energy. Numerically, it is proved that the potential soluble salts and surfce active substance. Sparingly soluble salts and surface acitve substances decrease the surface tension of the liquid. However, the fairly soluble solutes increase the surface tension of the liquid. Surfacetension of a liquid is independent of surface area but it depends on the intemolecular forces and the temperature. Surface tension of a liquid does not depend on : |
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Answer» temperature |
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| 13. |
Surface tension of a liquid…………..with increase in magnitude of intermolecular forces. |
| Answer» SOLUTION :INCREASES | |
| 14. |
Surface of alkali metals get dulled in presence of humid air. Because ... |
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Answer» SULPHIDE LAYER is formed on their surface. |
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| 15. |
Suppose there is a tiny sticky area on the wall of a container of gas. Molecules hitting this area stick there permanently. Is the pressure greater or less than on the ordinary area of walls? |
| Answer» Solution :If the gas molecules STICK to the WALLS of the container. Then the number of molecules striking the walls of the container DECREASES. An decrease in the number of gas molecules in the same VOLUME container decreases PRESSURE. | |
| 16. |
Suppose the elements X and Y combine to form two compounds XY_(2) and X_(2)Y_(2). When 0.1 mole of XY_(2) weighs 10 g and 0.05 mole of X_(3)Y_(2) weighs 9 g, the atomic weights of X and Y are |
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Answer» 40, 30 |
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| 17. |
Suppose in the Bohar's model of H-atom, instead of electron forec, some other force is acting between nucleus & electronwhich cause thepotential energy to vary as -(K)/(6r^(6)). Assuing Bohar's quantizationof angular momentum.(Given : Mass o fan electron =m) (i) Derive expression for radiusof n^(th) orbit(ii)Given the expression to obitain energy of such a hydpotheticalatoms . |
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Answer» `mvr=(NH)/(2PI)……..(2)""F=(du)/(dr)=-((-6)r^(-7)k)/(6)` "subsituting" `V=(nh)/(2pimr)," inequation (1)"` `m((nh)/(2pimr))^(2)=(k)/(r^(6))` `r^(4)=(4pi^(2)mk)/(N^(2)h^(2))""rArr=((2pi)/(n h))^(1//2)(mK)^(1//4)` T.E`=(1)/(2)mv^(2)+(-(k)/(6r^(6)))` `=(K)/(2r^(6))-(K)/(6r^(6))`=`(k)/(r^(6))[(1)/(2)-(1)/(6)]=(k)/(r^(6))[(3-1)/(6)]` T.E.`=(k)/(3R^(6))`=`(k)/(3((2pi)/(nh))^(6//2)(mk)^(6//4))`=`((n^(3)h^(3))/(24pi^(3)))((1)/(m^(3//2)sqrtK))` |
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| 18. |
Suppose that the uncertainty in determining the position of an electron in an orbit is 0.6A what is the uncertainty in its momentum? |
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Answer» <P> Solution :`/_\x=`uncertainty in position of an electron`=0.6A=0.6xx10^(-10)m``/_\p`=uncertainty in momentum=? Heisenberg.s uncertainty principle states that, `/_\p=h/(4pi./_\x)` h=planck.s constant`=6.626xx10^(-34)kg m^(2)s^(-1)` `:./_\p=(6.626xx10^(34)kgcancel(m^(2)s^(-1)))/(4xx3.14xx0.6xx10^(-10)CANCEL(m))` `=(6.626xx10^(-34)xx10^(10))/(7.536)` uncertainty in momentum`=0.8792xx10^(-24)kgms^(-1)(or)` `=8.792xx10^(-25)kgms^(-1)` |
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| 19. |
Suppose the chemists had selected 10^20 as the number of particles in a mole. The molar mass of oxygen gas would be (Use Avogadro number = 6.0 xx 10^23) |
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Answer» `5.33xx10^(-3)g` 1 molecule of oxygen weighs `(32)/(6xx10^(23))` `10^(20)` molecules of oxygen weighs `(32xx10^(20))/(6xx10^(23))=5.33xx10^(-3) g` |
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| 20. |
Suppose that a reaction has Delta H= -400kJ and Delta S = - 50J//K. A t what temperature range will it change from spontaneous to non-spontaneous? |
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Answer» 0.79K to 0.81 K `-40 xx 1000 - T(-50) lt 0` `-40000 + 50T lt 0` `50T lt 40000` `T lt 800K` it is spontaneous |
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| 21. |
Suppose a particle has four quantum numbers such that the permited values are those as given below: n,1,2,3... l: (n-1), (n-3),(n-5)...but no negative number J:(//+(1)/(2)) or (//-(1)/(2)) if the latter is not negative. m : J in integral steps to +J Thus, how many particles could be fitted into that n = 2 shell? |
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Answer» |
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| 22. |
Suppose a completely filled or half fillled set fo ( p) or d-orbitials is spherically symmetrical : |
| Answer» SOLUTION :`CI^(-)` has ` ns^2 np^6` CONFIGURATION . | |
| 23. |
Suppose a chemist has chosen 10^(20) as the number of particles in a mole. What would be the molecular mass of oxygen gas ? |
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Answer» 1.0 MOLECULE of oxygen weighs `= (32)/(6.022xx10^(23))=5.31xx10^(-23)g` `:.` Mass of `10^(20)` molecules of oxygen `= 5.31 xx 10^(-23) xx 10^(20) = 5.31 xx 10^(-3)g`. |
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| 24. |
Suppose 10^(-18)J of light energy is needed by the interior of the human eye to see an object. How many photon of green light (lambda = 550nm) are needed to generate this amount of energy ? |
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Answer» `=3.61xx10^(-19) J = `1 Photon `10^(-18) J = (10^(-18))/(3.61xx 10^(-19)) = (10)/(3.61) = 2.77 = 3` |
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| 25. |
Supply thereagentsin thefollowingsequenceof reations : (iv) CH_(3) -CH =CH_(2) overset([A])(to) CH_(3) CH_(2) CH_(2)Br overset([B])(to)C_(6)H_(5)CH_(2) CH_(2) CH_(3) |
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Answer» Solution :`underset("Propene")(CH_(3)-CH=CH_(2) ) overset(HBr//ROOR [A])underset("Anti-Mark")(to) underset(1-"Bromopropane")(CH_(3)CH_(2)CH_(2)Br) overset(C_(6)H_(5)MgBr)underset(("GrigN/Ard reaction "))(to) underset("n- Propylbenzene")(C_(6)H_(5)CH_(2)CH_(2)CH_(3))` `"AlterN/Atively " underset(1-"BromopropN/Ae")(CH_(3)CH_(2)CH_(2)Br) overset(C_(6)H_(5)Br, N/A[B])underset(("Wurtz-Fittingreaction"))(to) underset("n-Propylbenzene")(C_(6)H_(5)CH_(2)CH_(2)CH_(3))` |
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| 26. |
Support the acidic nature of silica |
| Answer» Solution :Silica is ACIDIC. On fusion with metal oxides or carbonates, it forms silicates like `Na_(2)SiO_(3),CaSiO_(3)`, etc. | |
| 27. |
Supply thereagentsin thefollowingsequenceof reations :(ii) CH_(4) overset([A])(to) CH_(3) Br overset([B]) (to)C_(6) H_(5) CH_(3)overset([C])(to) C_(6)H_(5)COOH |
| Answer» Solution :`underset("Methane")(CH_(4)) overset(Br_(2)//hv [A])(to) CH_(3)Br overset(C_(6)H_(6)." ANHYD." AICI_(3)[B])underset("(F.C. alkylation)")(to)underset("Toluene")(C_(6)H_(5)CH_(3)) overset((i) KMnO_(4),KOH, 373 K[C])underset((II) H_(3)O^(+))(to) underset("Benzoic acid")(C_(6)H_(5)COOH)` | |
| 28. |
Supply thereagentsin thefollowingsequenceof reations : (i) CH_(3)CH_(2)CH_(2)Br overset((A))(to) CH_(3) CH= CH_(2) overset((B))(to) CH_(3) CHBr - CH_(2) Br overset((C ))(to) CH_(3)-C -=CH overset((D))(to) CH_(3) -overset(O)overset(||)(C)-CH_(3) |
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Answer» Solution :`underset(1-"Bromopropane ")(CH_(3)CH_(2)CH_(2)Br) overset(KOH al. Delta [A])underset("(Dehydrobromiation)")(to) underset("PROPENE")(CH_(3)CH=CH_(2)) overset(Br_(2),CCI_(4)[B])(to) underset(1,2-"Dibromorpropane")(CH_(3)CH_(2)Br-CH_(2)Br)` `overset(KOH alc. Delta [C])underset("(DehydrobromiN/Ation)")(to) underset("Propyne")(CH_(3) -C -=H) overset(" Dil. "H_(2)SO_(4), HgSO_(4) [D])underset(330k)(to) CH_(3) -overset(O)overset(||)(C) -CH_(3)` |
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| 29. |
Superphosphate of lime is |
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Answer» PRIMARY calcium phosphate and epsom |
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| 30. |
Superoxides of alkali metals act as oxidising agents while normal oxids are basic in nature. The oxide which is paramagnetic in nature due to presence of unparied electron is |
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Answer» `Na_(2)O_(2)` |
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| 31. |
Supercritical CO_(2)is used as |
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Answer» dry ice |
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| 32. |
Superconductors are derived from the compounds of |
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Answer» p-block ELEMENTS |
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| 34. |
Super conductors are derived from compounds of |
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Answer» p-block ELEMENTS |
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| 35. |
Summerize primary information about water pollution. |
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Answer» Solution :Water is ESSENTIAL for life. Without water there would be no life. We usually take water as granted for its purity, but we must ensure the quality of water. Pollution of water originates from human activities. Pollution reaches SURFACE or ground water through different paths. Easily identified SOURCE or place of pollution is called as point source. e.g., municipal and industrial discharge pipes. A source of sources of pollution are those where a source of pollution cannot be easily identified, e.g., agricultural run off (from farm, animals and crop-lands), acid rain, storm-water drainage (from STREETS, parking lots and lawns), etc. The major water pollutants and their sources are listed below : 
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| 36. |
Summarize the quantities and differentiated quantities of different metals and ions at the international level of drinking water. |
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Answer» Solution :The international standards for drinking water are given below: (i) Fluoride : Fluoride ion concentration should be tested in drinking water. Its deficiency in drinking water is harmful to man and causes diseases such as tooth decay etc. Soluble fluoride is often added to drinking water to bring its concentration upto 1 ppm or 1 MG `DM^(-3)` . The `F^(-)` ions MAKE the enamel on teeth much harder by converting hydroxyapatite, `[3(Ca_3 PO_4)_2 Ca(OH)_2]`, the enamel on the surface of the teeth, into much harder fluorapatite `[3 (Ca_3 PO_4)_2. CaF_2]`. If `F^(-)` ion concentration above 2 ppm causes brown mottling of teeth. Whereas if `F^(-)` ion concentration is more than 10 ppm it causes harmful effect to bones and teeth. It is reported from some parts of Rajasthan. (ii) Lead : Drinking water gets contaminated with lead when lead pipes are used for transportation of water. The prescribed upper limit concentration of lead is about 50 ppb lead can damage kidney, liver, reproductive system etc. (iii) Sulphate : Excessive sulphate (`gt` 500 ppm) in drinking water causes laxative effect, otherwise at moderate levels it is harmless. (iv) Nitrate : The maximum limit of nitrate in drinking water is 50 ppm. Excess nitrate in drinking water can cause DISEASE like methemoglobinemia (blue baby. SYNDROME). (v)Other metals : The maximum concentration of some common metals recommended in drinking water. Which are given in table. 
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| 37. |
Summarize the Bohr's Model of an atom. |
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Answer» SOLUTION :Bohr's Model of an atom, the POSTULATES are (1) Electrons revolve around the nucleus 'of an atom in a certain definite path called orbit or stationary state of shell. (2) The shells are having different energy levels denoted as K, L, M, N ... (3) As long as th~ electron remains in an orbit, they neither absorb nor emit energy. (4) The electron can move only in that orbit in which angular momentum is quantized, i.e., the angular momentum of the electron is an integral multiple of `h/(2pi)` |
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| 38. |
Sum of the oxidation numbers of carbon in acetaldehyde is |
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Answer» `-2` `2X +4(+1)+1(-2)=0` 2x = - 2 |
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| 39. |
Sum of spin quantum number values of all the electrons in Gd(z=64) is |
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Answer» |
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| 41. |
Sum of first three ionisation energies of Al is 53-03 eV atom^(-1) and the sum of first two ionisation energies of Na is 52 20 eV atom^(-1) Out of Al(II) and Na(II) |
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Answer» NA(II) is more stable than AL(III) |
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| 42. |
Sulphurtrioxide is prepared by following two reaction : (i) Cu_(2)S + O_(2) rarr Cu_(2) O + SO_(2) (ii) 2SO_(2) + O_(2) rarr 2SO_(3) How many gramSO_(3) of are produced from 159 g of Cu_(2)S (Atomic mass of Cu = 63.5, S = 32, O = 16 g/mole) |
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Answer» Solution :(i) `Cu_(2)S + O_(2) rarr Cu_(2) O + SO_(2)` Mw.of `Cu_(2)S= 159` g/mole So, 159 g `Cu_(2)S` willproduce 1 mole of `SO_(2)(64 g SO_(2))` (ii) `2SO_(2) + O_(2) rarr 2SO_(3)` `128 g SO_(2)` will produce `160 g SO_(3)` `:.64 g SO_(2)` will produce `80 g SO_(3)` |
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| 43. |
Sulphuricacid reacts with sodium hydroxide as follows : H_(2)SO_(4) + 2NaOH rarr Na_(2)SO_(4) +2H_(2)O When 1 L of 0.1M sulphuric acid solution is allowed to react with 1L of 0.1 M sodium hydroxide solution, the amount of sodium sulphate formed and its molarity in the solution obtained is |
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Answer» 0.1 mol `L^(-1)` `H_(2)SO_(4) +2NaOH rarr Na_(2)SO_(4) +2H_(2)O` 1 L of 0.1M `H_(2)SO_(4)` contains `=0.1` mole of `H_(2)SO_(4)` 1 L of 0.1 M NaOH contains `=0.1` mole of `H_(2)SO_(4)` ACCORDING to the reaction, 1 mole of `H_(2)SO_(4)` reacts with 2 MOLES of NaOH will react with 0.5 mole `H_(2)SO_(4)` and 0.05 mole of `H_(2)SO_(4)` will remain unreacted i.e., NaOH is the limiting reactant. Since, 2 moles of NaOH produces 1 mole of `Na_(2)SO_(4)`. Hence, 0.1 mole of NaOH will produce 0.05 mole of `Na_(2)SO_(4)`. Mass of `Na_(2)SO_(4) = "moles" xx "molar mass"` `= 0.5xx(46+32+64)g` `= 7.10g` Volume of solution after mixing `=2L` Since, only 0.05 mole of `H_(2)SO_(4)` is left behind as NaOH completely used in this reaction. Therefore, molarity of the given solution is calculated from moles of `H_(2)SO_(4)`. `H_(2)SO_(4)` left unreacted in the solution `= 0.05` mole Molarity of the solution `= (0.5)/(2) = 0.025 "mol" L^(-1)` |
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| 44. |
Sulphurly chloride (SO_(2)Cl_(2)) reacts with white phosphorus (P_(4)) to give |
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Answer» `PCl_(5),SO_(2)` `P_(4)(s)+10SO_(2)Cl_(2)(l)to4)PCl_(5)(s)+10SO_(2)(g)` |
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| 45. |
Sulphuric acid oxidises hydroiodic acid to iodine and forms hydrogen sulphide and water. |
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Answer» Solution :a) The SKELETON equation is written as `H_(2)SO_(4)+HIrarrH_(2)S+I_(2)+H_(2)O` b) Focusing on the oxidation NUMBERS `overset(+1)(H_(2))overset(+6)(S)overset(-2)(O_(4))+overset(+1)(H)overset(-1)(I)rarroverset(+1)(H_(2))overset(-2)(S)+overset(0)(I_(2))` c) Locating atoms undergoing CHANGE in oxideation numbers `H_(2)overset(+6)(SO_(4))+Hoverset(-1)(I)rarrH_(2)overset(-2)(S)+overset(0)(I_(2))` d) Determining the change in oxidation numbers  e) Cris - crossing these changes in the oxidation numbers `H_(2)SO_(4)+8HIrarrH_(2)S+I_(2)` f) Balancing HTE atoms other than hydrogen and oxygen `H_(2)SO_(4)+8HIrarrH_(2)S+4I_(2)+H_(2)O` g) Blancing the atoms hydrogen and oxygen `H_(2)SO_(4)+8HIrarrH_(2)S+4I_(2)+4H_(2)O` This is the balanced EQUATIONS. |
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| 46. |
Sulphur trioxide is prepared by the following two reactions: S_(8(s))+8O_(2(g))to8SO_(2(g)),2SO_(2(g))+O_(2(g))to2So_(3(g)) How many grams of SO_(3) are produced from 1.6 g S_(8) ? |
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Answer» `256g_______8xx64=512g` `1.6g_______3.2g` `2SO_(2(g))+O_((2)g)rarr2SO_(3(g))` `2xx64` `=128g______2xx80=160g` `3.2g______(3.2xx160)/(128)=4G` |
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| 47. |
Sulphur molecules exist under various conditions as S_(8), S_(6), S_(4), S_(2) and S. (a) Is the mass of one mole of each of these molecules the same? (b) Is the number of molecules in one mole of each of these molecules the same? (c) Is the mass of sulphur in one mole of each of these molecules the same? (d) Is the number of atoms of sulphur in one mole of each of these molecules the same? |
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Answer» |
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| 48. |
Sulphur impurity present in blue gas is removed by using |
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Answer» Cobalt |
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| 49. |
Sulphur forms the chlorides S_(2)Cl_(2) and SCl_(2).The equivalent mass of sulphur in SCl_(2) is |
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Answer» 8 g/mol In `SCl_(2)` valency of sulphur `=2` So equivalentmass of sulphur `= 32/2 = 16` |
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| 50. |
Sulphur follows law of mutiple proportions to combine with halogens. Calculate the equivalen weight of sulphurwhen it form SCl_(2) and S_(2)Cl_(2) |
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Answer» |
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