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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 can we measure atomic radius ? |
| Answer» Solution :ATOMIC RADIUS is measured by X-ray spectra or X-ray or other SPECTROSCOPIC methods. | |
| 2. |
How can the production of dihydrogen , obtained from coal gasification, be increased? |
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Answer» Solution :The process of producting syngas or synthesis gas from coal is called 'coal gasification'. ` underset("Coal")(C(s))+ underset("Steam")(H_(2)O(g)) underset(Ni)overset(1270K)to underset("Syngas")ubrace(Co(g)+H_(2)(g))` The production of hydrogen can be increased by reacting carbon monoxide of syngas with steam in presence of iron chromate as catalyst at 673 K . This is called water gas shift REACTION. `CO(g) + H_(2)O(g) overset(FeCrO_(4),673K)to Co_(2)(g) + H_(2)(g)` The `CO_(2)` thus produced is removed EITHER by scrubbing with a solution of sodium aresente or by passing the mixture through water under 30 ATM . Pressure when `CO_(2)` dissolves leaving BEHIND `H_(2)` which is collected. |
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| 3. |
About 18% of the total production of dihydrogen is from coal. What is 'coal gasification? |
| Answer» SOLUTION :COAL gasification involves the formation of water gas (syn gas) from coal or COKE by PASSING STEAM over it. Then CO is oxidised to `CO_2` and produccs more `H_2` from steam. | |
| 4. |
How can the spontaneity of reaction determine by the value of DeltaG^0 ? |
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Answer» Solution :`DeltaG LT 0` , i.e., negative So, REACTION is forward and products increase and K `gt` 1. `DeltaG gt 0`, i.e., POSITIVE, So, reaction is reverse and products decreases and K `lt` 1. `DeltaG = 0`, i.e., ZERO, So, reaction is in equilibrium and reaction is not occurs in any direction and K=1. |
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| 5. |
How can the production of dihydrogen, obtained from .coal gasification. be increased ? |
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Answer» Solution :(i) Electrolysis of acidified water using platinum electrodes gives hydrogen. `2H_2O_((l)) underset"Traces of acid/base"overset"Electrolysis"to 2H_(2(g)) + O_(2(g))` (ii) High purity (`gt`99.95 %) dihydrogen is obtained by electrolysing warm aqueous barium hydroxide solution between nickel electrodes. (iii) It is obtained as a byproduct in the manufacture of sodium hydroxide and chlorine by the electrolysis of brine solution. During electrolysis, the reactions that take place are : at anode : `2Cl_((aq))^(-) to Cl_(2(g)) + 2E^(-)` at cathode : `2H_2O_((l)) + 2e^(-) to H_(2(g)) + 2OH_((aq))^(-)` The overall REACTION is : `{:(2Na_((aq))^(+)+ 2Cl_((aq))^(-) + 2H_2O_((l))),(""darr),(Cl_(2(g)) + H_(2(g)) + 2Na_((aq))^(+) + 2OH_((aq))^(-)):}` (iv) Reaction of steam on hydrocarbons or coke at high temperatures in the presence of catalyst yields hydrogen. `C_n H_(2n+2) + nH_2O underset"Ni"overset"1270 K"to nCO+(2n+1)H_2` e.g. , `CH_(4(g)) + H_2O_((g)) underset"Ni"overset"1270 K"to ubrace(CO_((g))+3H_(2(g)))_("water gas ")` The mixture of CO and `H_2` is called water gas. As this mixture of CO and `H_2` is used for the synthesis of methanol and a number of hydrocarbons, it is also called synthesis gas or .syngas.. Nowadays .syngas. is produced from sewage, saw-dust, scrap wood, NEWSPAPERS etc. The process of producing .syngas. from coal is called .coal gasification.. `C_((s))+H_2O_((g)) overset"1270 K"to CO_((g)) + H_(2(g))` The production of dihydrogen can be increased by reacting carbon monoxide of syngas mixtures with steam in the presence of iron chromate as catalyst. `CO_((g))+ H_2O_((g)) underset"catalyst"overset"673 K"to CO_(2(g)) + H_(2(g))` This is called water-gas shift reaction. Carbon dioxide is removed by scrubbing with sodium arsenite solution. Presently - 77% of the industrial dihydrogen is produced from petrochemicals, 18% from coal, 4% from electrolysis of aqueous solutions and 1% from other sources. |
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| 6. |
How can the production of dihydrogen from 'coal gasification' be increased? |
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Answer» Solution :In coal gasification reaction,steam vapours are passed through coke to form MIXTURE of CO and `H_(2)` also called syn gas. `C(s)+H_(2)O(g) to ubrace(CO(g)+H_(2)(g))_("syn gas")` The production of dihydrogen can be INCREASED by reacting `CO(g)` present in syn gas with steam in hte presence of IRON chromate catalyst With the removal of `CO(g) or CO_(2)(g)`, the reaction shifts in the forward direction direction. This is KNOWN as water gas SHIFT reaction. As a result, the production of dihydrogen will increase. `CO(g)+H_(2)O(g) underset(673K) overset(FeCrO_(4)("catakyst"))to CO_(2)(g)+H_(2)(g)` |
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| 7. |
How can saline hydrides remove traces of water from organic compounds ? |
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Answer» Solution :Saline hydrides (i.e., `NaH,CaH_(2),`etc) REACT with water formingtheir corresponding metal hydroxides with the LIBERATION of `H_(2)` gas. Thus, traces of water present in organic solvents can be EASILY removed by distillingthem over saline hydrides when `H_(2)` escapes into theatmosphere, metal hydroxide it left in the flask while DRY organic solvent distils over. Alternatively, organic compounds containing traces of water can be dried by PLACING them in a desiccator containing saline hydrides at the bottom for a few hours or perferably overnight. |
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| 8. |
How can production of hydrogen from water gas be increased by using water gas shift reaction ? |
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Answer» Solution :Water gas is produced wh superheated eam is passed over red hot coke or coal at 1270 K in presence of nickel as catalyst `underset"Coke"(C_(s)) + underset"STEAM"(H_2O_((g))) + 121.3kJ underset"[Ni]"overset"1270 k"to ubrace(CO_((g)) + H_(2(g)))_("water gas")` It is difficult to obtain pure `H_2` from water gas as CO is difficult to remove. Therefore, to increase the production of `H_2` from water gas, CO is oxidised to `CO_2` by mixing it with more steam and passing the mixture over `FeCrO_4` catalyst at 673 K. `ubrace(CO_((g)) + H_(2(g)))_("water gas") +underset"steam"(H_2O_((g))) underset(FeCrO_4)overset"673k"toCO_(2(g)) + 2H_(2(g))` The chemical reaction in which CO of water gas reacts with steam to form `CO_2` and more `H_2` is called water gas shift reaction. (WGSIQ). `CO_2` from syngas this produced can be removed either by scrubbing the mixture with sodium arsenite solution or by passing the mixture through water under 30 atm pressure when `CO_2` dissolves leaving behind `H_2` which is collected. |
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| 9. |
How can one non - polar molecule induced a dipole in a nearby non - polar molecule? |
| Answer» Solution :In a NON - polar molecule, there may be instantaneous dipole created by specific positions of ELECTRONS. This instantaneous dipole can INDUCE a dipole in a nearby non - polar molecule. | |
| 10. |
How can domestic waster be used as manure ? |
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Answer» Solution :(1) Domestic wastes are collectedin small dustbins and carried to the disposable SITE. (ii) The garbages are sorted out as bio- degradable and non-biodegradable . (iii) Then, the bio- degradable wastes (EG: fruits, vegetables , animals WASTE, etc) are DEPOSITED in land fills and are coverted into manure. |
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| 11. |
How can domestic wastes be used as manure ? |
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Answer» Solution :(i) Domestic wastes are collected in small DUSTBINS and CARRIED to the DISPOSABLE site. (II) The garbages are sorted out as bio-degradable and non-biodegradable. (iii)Then, the bio-degradable wastes(Eg `:` fruits,vegetable, animal WASTE, etc ) are deposited in land fills and are converted into manure. |
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| 12. |
How can D_(2)O be prepared from water ? Mention the physical properties in which D_(2)Odiffers from H_(2)O . Give at least three reactions of D_(2)O showing the exchange of hydrogen with deuterium. |
| Answer» SOLUTION :`D_(2)O` is prepared by PROLONGED electrolysis of ordinary water. | |
| 13. |
How can domestic waste be used as manure ? |
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Answer» Solution :According to its nature, domestic waste is classified in two TYPES : (i) Biodegradable substance (II) Non-biodegradable substance Biodegradable waste such as LEAVES, ripe fruit etc. should be buried in the soil so that it is decomposed and it is useful. Non-biodegradable waste such as plastic, GLASS, metal scrap etc. should be recycled. |
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| 14. |
How can decide which triatomic molecules are linear of the following ? H_(2)O, F_(2) O, BeH_(2), BeCl_(2) , H_(2)S, CO_(2) |
| Answer» Solution :`BeH_(2), BeCl_(2) , CO_(2)` are linear. Experimentally its dipole MOMENT is zero so DECIDE that these TRIATOMIC MOLECULES are linear. | |
| 15. |
How can domestic waste be used as mannure? |
| Answer» Solution :Biodegradable waste (VEGETABLE matter, food ETC) can be CONVERTED into COMPOST. This is a good biofertilise. Non-biodegradable waste (plastics, metal, glass etc) can be recycled and used again. | |
| 16. |
How can D_2O be prepared from water ? Mention the physical properties in which D_2O differs from H_2O. Give at least three reactions of D_2O showing the exchange of hydrogen with deuterium. |
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Answer» Solution :`D_2O`is prepared by prolonged electrolysis of water. Physical properties : (i) `D_2O`is colourless, ODOURLESS and tasteless liquid. Its MAXIMUM density is `-1.1073 GML^(-1)`It `11.6^@C` maximum density of water is `4^@C`. (ii) The solubility of salt in heavy water is LESS than ordinary water. So, the viscosity is HIGH of heavy water. (iii) Exchange reactions of hydrogen with deuterium `NaOH+D_2OtoNaOD+ HOD` `HCl+ D_2O to DCl + HOD` `NH_4Cl + D_2O to NH_3DCl + HOD` |
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| 17. |
How can a material be made amorphous ? Give an example of supercooled liquid. |
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Answer» SOLUTION :By melting the material and then cooling it rapidly. GLASS. |
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| 18. |
How can a material be made amorphous ? |
| Answer» SOLUTION :By MELTING the MATERIAL and then COOLING it RAPIDLY | |
| 19. |
How beryllium is anomalous from alkaline earth metal elements? |
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Answer» SOLUTION :Beryllium, the first member of the Group-2 metals, shows anomalous BEHAVIOUR as compared to magnesium and rest of the members. Further, it shows diagonal relationship to aluminium which is DISCUSSED subsequently. (i) Beryllium has exceptionally small atomic and ionic sizes and thus does not compare well with other members of the group.Because of high ionisation enthalpy and small size it forms COMPOUNDS which are largely covalent and get easily hydrolysed. (ii) Beryllium does not exhibit coordination number more than four as in its valence shell there are only four orbitals. The remaining members of the group can have a coordination number of six by making use of d-orbitals. (iii) The oxide and hydroxide of beryllium, unlike the hydroxides of other elements in the group, are amphoteric in NATURE. |
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| 20. |
How beryllium chloride is prepared from beryllium oxide? |
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Answer» Solution :`BEO + C + Cl_(2)OVERSET( 600 - 800K)to BeCl_(2) + CO` Beryllium oxide is heated with carbon and chloride to GET `Becl_(2)` |
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| 21. |
How benzene can be prepared by griganrd reagent |
| Answer» Solution :PHENYL magnesiumbromide reagentreactswith watermoleculeto givebenzene : <BR> `C_(6) H_(5) MGBR + H_(2)O toC_(6)H_(6) + MG (OH) Br` | |
| 22. |
How are the hyperconjugating structures drawn ? |
Answer» Solution :The hyperconjugating structures are drawn by separating the `alpha` - hydrogen from rest of the molecule .For example ,the hyperconjugating of PROPANE are drawn as FOLLOWS .  In the above resonating structures ,there is no COVALENT bond between carbon and one of the hydrogens that is why it is KNOWN as no -bond RESONANCE . |
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| 23. |
How are the following related ? ( Give mathematical relation ) (i) Free energy change and electrical work . (ii) Free energy change, enthalpy change and entropy change. |
| Answer» Solution :(i) ELECTRICAL work done `(nFE) = - Delta G` (ii) `DELTAG = DELTAH - T DELTAS`. | |
| 24. |
How are the D_2Omolecules in deuterates present ? Give examples each. |
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Answer» Solution :Three types of DEUTERATES MAY be formed on similar lines with water. They are : i) Deutero BONDED compounds (similar to HYDROGEN bonded compounds). `CuSO_4. 5D_2O` ii) Interstitial deuterates. `BaCl_2 . 2D_2O` iii) Coordination compounds : `CrCl_3. 6D_2O` |
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| 25. |
How are reducing agents in synthetic organic chemistry prepared? |
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Answer» Solution :Hydrogen has a tendency to react with reactive metals like lithium, SODIUM to give corresponding hydrides `2Li+H_(2)to2LiH` `2Na+H_(2)to2NaH` These hydrides are USED as reducing agents in synthetic organic CHEMISTRY. It is ALSO used to prepare important hydrides such as lithium aluminium hydride and sodium boro hydride (organic reducing agents). `4LiH+AICI_(3)TOLI[LiH_(4)]+3LiCI` `4 Nalt B(OCH_(3))_(3)toNa[BH_(4)]+3CH_(3)ONa` |
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| 26. |
How are peroxides and superoxides formed by alkali metals? |
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Answer» Solution :(i) he FACT that a small cation can stabilize a small anion and a large cation can stabilize a large anion explains the formation and stability of these oxides. (ii) The `Na^+` ion is a LARGER cation and has a weak POSITIVE field around it and THUS can stabilize a bigger peroxide ion, `O_2^(2-)` or `[-O-O-]^(2-)` Which is also surrounded by a weak neagative field. (iii) Similarly, the other ion `K^+,Rb^+,Cs^+` are still larger, having very weak positive field. Thus these IONS can stabilize a bigger superoxide `O^(2-)` anion and form super oxides. |
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| 27. |
How are oxides of nitrogen harmful to ozone concentration? |
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Answer» Solution :Both `NO and NO_(2)`REACT with `O_3`to GIVE `O_2` `NO +O_(3) rarr NO_(2)+O_2` `NO_(2)+O_(3) rarr NO+2O_(2)` |
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| 28. |
How are NO and NO_2 formed in the atmosphere ? |
| Answer» Solution :NO is formed DUE to REACTION between `N_2` and `O_2` during lightning or COMBUSTION of FOSSIL fuels. It is further OXIDIZED to `NO_2` | |
| 29. |
How are naphthalene and camphor purified? |
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Answer» Solution :(i) Naphthalene, CAMPHOR and benzoic acid when heated, pass directly from solid to vapour without melting. On cooling the vapours will give back solid. This PHENOMENON is known as sublimation. This technique is used to purify naphthalene, camphor from NON volatile impurities. (ii) Substances to be purified is taken in a beaker. It is covered with a watch glass. The beaker is heated for a while and the resulting vapours CONDENSE on the bottom of the watch glass. Then the watch glass is removed and the crystals are COLLECTED. |
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| 31. |
How are K_(p)andK_(c) related? Mention the condition under which K_(p)=K_(c). |
| Answer» SOLUTION :`K_(p)=(RT)^(Deltan)`. When `Deltan` = 0 i.e., number of moles of the GASEOUS PRODUCTS = number of moles of the gaseous reactants. e.g., `H_(2)(g)+I_(2)(g)hArr2HI_(g)-K_(p)=K_(c)` | |
| 32. |
How are internal energy change( at constant pressure) , free energy change and entropy change related to one another? |
| Answer» SOLUTION :`DeltaH = DeltaH -T DELTAS .(DeltaH=` INTERNALENERGY change at CONSTANT pressure). | |
| 33. |
How are frequency and wave number related to each other ? |
| Answer» Solution :`c = v lamda = v = (1)/(BAR(v)) or v = c bar(v)`, where c is VELOCITY of light, v is FREQUENCY and `bar(v)` is WAVE number. | |
| 34. |
How are formic acid molecular are associated? |
| Answer» SOLUTION :FORMIC ACID molecules are associated with inter MOLECULAR hydrogen bonding. | |
| 35. |
How are flue gases from industries freed from oxides of nitrogen and sulphur ? |
| Answer» Solution :By scrubbing them with CONC. `H_2SO_4` or with alkaline SOLUTIONS like `Ca(OH)_2` and `MG(OH)_2` | |
| 36. |
How are electronegative and metallic & non-metallic characters related? |
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Answer» |
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| 37. |
How are 2 mole NaOH and 2 Molar NaOH different? |
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Answer» Solution :2 mole NaOH 1 mole of NaoH `=40g` of NaOH `=6.023xx10^(22)` MOLECULES 2 mole of NaOH `2xx40g=80g` of NaOH `=2xx6.023xx10^(23)` molecules. 2 MOLAR NaOH 1 molar `NaOH=40g` of NaOH in 1000 ml of WATER 2 molar NaOH `=80g` of NaOH in 100 ml of water `=2` moles of NaOH dissolved in 1000 ml of its solution. |
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| 39. |
How are 0.50 mol Na_(2)CO_(3) and 0.50 M Na_(2)CO_(3) different ? |
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Answer» `= (2 xx 22.99) + 12.01 + (3 xx 16)` `= 105.99 ~~ 106` gm/mole 0.5 mole `Na_(2)CO_(3) = 0.5 xx 106` `= 53 gm Na_(2)CO_(3)` So, 0.5 mole `Na_(2)CO_(3)` MEANS 53 gm `Na_(2)CO_(3)` present in 1 litre solution. |
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| 40. |
How are 0.50 mol Na_(2)CO_(3) and 0.50 M Na_(2)CO_(3) different? |
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Answer» Solution :Molar MASS of `Na_2CO_3 = (2 XX 23) + 12 + (3 xx 16) = 106` 0.50 mol `Na_2CO_3` means `0.50 xx 10^6 = 53` g of `Na_2CO_3`. It refers to the mass only.`0.50 M Na_2CO_3` means 0.50 mol, i.e., 53 g of `Na_2CO_3` are present in 1 litre of the solution. Thus, it refers to the strength of the solution. |
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| 41. |
How ammonia is manufactured from Hydrogen? Give the uses of ammonia. |
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Answer» SOLUTION :(i) Ammonia is manufactured by Haber.s PROCESS in which the largest consumer of HYDROGEN is used. `N_(2(g))+3H_(2(g))leftrightarrow2NH_(3(g))` (ii) Ammonia is employed for the manufacture of nitric ACID, fertilizers and explosives. |
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| 42. |
How alkali metals react with water? Give an equation? |
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Answer» SOLUTION :The most reactive alkali metals DECOMPOSE water in the COLD with the evolution of hydromen and leaving an alkali solution. `2Na_((s))+2H_(2)O_((L))to2NaOH_((aq))+H_(2(g))` |
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| 43. |
How alkali metals react with oxygen? Explain with equation. |
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Answer» Solution :All the alkali metals on EXPOSURE to air burn vigorously, forming oxides on the surface of the metals (ii) Lithium forms only monoxide, SODIUM forms the monoxide and peroxide and the other elements form monoxide, peroxide and superoxides. `4Li + O_(2) to 2Li_(2)O` (Lithium monoxide) ` 2 Na + O_(2) + Na_(2)O_(2)` (Sodium peroxide) `K + O_(2) to KO_(2)` (POTASSIUM superoxide) |
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| 44. |
How alkali metals react with liquid ammonia? |
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Answer» Solution :Alkali metals dissolve in liquid ammonia to give deep blue solutions that are conducting in nature, . (ii) This happens because the alkali metal atom readily loses the valence electron in ammonia solution. (iii) Both the CATION and the electron COMBINE with ammonia to FORM ammoniated cation and ammoniated electron. `M+(x+y)NH_(3)to[M(NH_(3))_(x)]^(+)+[E(NH_(3))_(y)]^(-)` |
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| 45. |
How acetic acid can be converted to benzene? |
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Answer» SOLUTION :`CH_3COOH overset(NaOH_((aq)))(rarr) CH_3COONa underset(Detla)overset("SODA lime")(rarr)CH_4` `underset(hv)overset(Cl_2)(rarr)CH_3Cl underset("Wurtz reaction")overset("Na/dryether")(rarr)C_2H_6overset(Cl_2)(rarr)C_2H_5Cl` `overset("alc. KOH")(rarr)CH_2 = CH_2overset(Br_2)(rarr)overset(CH_2Br)overset(|)(CH_2Br)overset(alc. KOH)(rarr)` `CH_2 =CHBR overset(NaNH_2)(rarr)CH -=CH underset(873K)overset("RED hot FE")(rarr)` 
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| 46. |
How acetaldehyde is commercially preparcd by grecn chemistry? |
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Answer» Solution :ACETALDEHYDE is commercially repared by once STEP OXIDATION of ethene in the presence of ionie catalyst in aqueous medium with 90% YIELD. `CH_(2) = CH_(2) overset("Catalyst")underset(underset([O])"Pd(II)//CU(II)")rarr underset("Acetaldehyde")(CH_(3)CHO)` |
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| 47. |
How 2-cthylanthraquinone helps to prepare hydrogen peroxide? |
Answer» SOLUTION : On an industrial SCALE, hydrogen peroxide is PREPARED by AUTO OXIDATION of 2-alkyl anthraquinol
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| 48. |
hotochemical smog occurs in warm, dry and sunny climate. One of the following is not amongst the components of photochemical smog. Identify it. |
| Answer» Solution :`NO_(2)` | |
| 49. |
Hot copper turnnings can be used as "oxygen getter" for inert gas supplies by slowly passing the gas over the copper tumning at 650 K. 2Cu_((s)) + (1)/(2) O_(2(g)) hArr Cu_(2) O_((s)) : K_(p) = 7.5 xx 10^(10) How many molecules of O_(2)are left in 1 Lof a gas supply after equilibrium has been reached ? |
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Answer» <P> `PO_(2)=(1)/((7.5 xx 10^(10))^(2))=1.778xx 10^(-22)` atm `pv = nRT implies n=(1.778 xx 10^(-22))/(0.0821 xx 650)` `=3.3318 xx 10^(-24)` Molecular = `n xx N` `=3.3318 xx 10^(-24) xx 6 xx 10^(23)=2` |
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