Explore topic-wise InterviewSolutions in Current Affairs.

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1.	SO_2 dissolve in water produces
Answer» `H_(2)SO_(4)` `H_(2)SO_(3)` `SO_(3)` `SO_(4)` Answer :B

2.	SO_2 can be obtained from which of the following reaction?
Answer» Reaction with DIL. `H_2SO_4` with `O_2` Hydrolysis of dil. `H_2SO_4` Reaction of CONC. `H_2SO_4` with Cu NONE SOLUTION :`Cu+2H_2SO_4 to CuSO_4 + SO_4 + 2H_2O`

3.	SO_2 can be used as:
Answer» BLEACHING agent Disinfectant Antichlor All Answer :D

4.	SO_2 acts as oxidising and reducing agent.
Answer» ANSWER :1

5.	SO_(2) bleaches by
Answer» Reduction OXIDAITON Hydrolysis ACIDIC NATURE Answer :A

6.	SO_2 can act as strong oxidising agent in:
Answer» ACIDIC medium Basic medium Neutral medium None Answer :C

7.	SO_(2) and CO_(2) both lime water (A) milky ,SO_(2) alsoturns K_(2)Cr_(2)O_(7)//H^(o+)(B) green O_(2) is solutionin pyrogallal (C ) turmingit black .Thesegasesareto the detected in order by usingthesereagents .The order is
Answer» (A),(B) ,(C ) (B),(C) ,(A) (B),(A) ,(C ) (A),(C) ,(B) ANSWER :c

8.	SO_2 and CH_4 are introduced in a vessel in the molar ratio 1:2.The ratio of molecules of two gases present in the container when their rate of effusion becomes equal is :
Answer» `1:2` `2:1` `4:1` `1:4` SOLUTION :`r=prop p/sqrtM` `p_1/sqrtM_1=p_2/sqrtM_2` `p_1/p_2=sqrtM_1/sqrtM_2=n_1/n_2 IMPLIES n_(SO_2)/n_(CH_4)=SQRT(M_(SO_2)/M_(CH_4))=sqrt(64/16)=2`

9.	SO_2acts as a bleaching agent. How?
Answer» Solution :In the PRESENCE of moisture, `SO_2` gives nascent hydrogen which REDUCES the colouring MATTER to a colourless compound. `SO_2 + 2H_2 O RARR H_2SO_4 + 2H` Vegetable colouring matter ` +H rarr ` Colouless matter

10.	SO_(2) acts as a/an
Answer» bleaching agent oxidation agent REDUCING agent DISINFECTANT Solution :All OPTIONS are CORRECT.

11.	SnO_(2) forms a positively charged colloidal sol in acidie medium and a negatively charged sol in the basic medium. Why ? Explain .
Answer» Solution :`SnO_(2)` is ampotericin nature. It reacts with ACID, e.g, with HCL to form `SnCl_(4)` in the solution. The common `Sn^(4+)` ions are adsorbed on the SURFAC of `SnO_(2)` particles thereby giving them a positive charge `SnO_(2)+4HCl to SnCl_(4)+2H_(2)O` `SnO_(2)+Sn^(4+)to underset("POSITIVELY charged colloidal particles")([SnO_(2)]:Sn^(4+))` `SnO_(2)` reacts with a base, e.g., NaOH to form sodium stannate `(Na_(2)SnO_(3))` in the solution. The stannate ions are adsorbed on the surface of `SnO_(2)` particles giving them an negative charge. `SnO_(2)+2NAOH to underset("Sodium stannate")(Na_(2)SnO_(3)+)H_(2)O` `SnO_(2)+SnO_(3)^(2-)to underset("Negatively charged colloidal particles")([SnO_(2)]:SnO_(3)^(2-))`

12.	SnO_2 forms a positively charged colloidal sol in the acidic medium and negatively charged sol in the basic medium. Explain.
Answer» SOLUTION :`SnO_2` is of AMPHOTERIC in nature which means that it can react with both acids and bases. With an acid such as HCL, if forms `SnCl_4`. The` Sn^(4+)` ions are adsorbed on the surface of `SnO_2` to give a POSITIVELY charged colloidal sol. `SnO_2+4HCl to SnCl_4+2H_2O and SnO_2+Sn^(4+) to [SnO_2]Sn^(4+)` Similarly with base like NaOH, if forms SODIUM stannate `(Na_2SnO_3)`. The stannate ions get adsorbed on the surface of SnO2 to give negatively charged colloidal sol. `SnO_2+2NaOH to Na_2SnO_3 and SnO_2+SnO_3^(2-) to [SnO_2] SnO_3^(2-)`

13.	SnCl_(4)stannic chloride hydrolyses in dilute solution as per given reaction SnCl_(4)+4H_(2)Oto[Sn(OH)_(4)]+4HCl. Hydrolysis can be repressed by adding compound "A".SnCl_(4)+A to B, B can be:
Answer» `Sn(OH)_(4)` `SnCl_(2)` `H_(2)SnCl_(6)` `Sn(OH)CL` SOLUTION :N//A

14.	SnCl_(2) + HCl convert
Answer» `-CHO` to `-CH_(2),-OH` `gt C=O` to `gtCH-OH` `-NO_(2)` to `-NH_(2)` `-NO_(2)` to =NOH Answer :D

15.	SN^2 reactions of alkyl halides is a bimolecular reaction which take place through formation of a transition state. The rate of reaction depends on the concentration of alkyl halide andnucleophile.The reaction is favoured by strong nucleophlie in polar aprotic solvents.Which of the following undero substitution by SN^2 mechanism at a faster rate from other
Answer» `CH_3CH_2CH_2Br`<BR>`CH_2 = CH - CH_2 - Br` `CH -= C - CH_2Br` all the above SOLUTION :`CH -= C - CH_2 - Br to ` SP (more E.N) , `E.N propE.W.G prop SN^2`

16.	S_(N)2 reactions are much faster in the solvents like
Answer» dimethyl formamide dimethyl sulphoxide hexamethyl phosphoramide alcohol-water mixture. Solution :`S_(N)2` is always FAVOURABLE in POLAR APROTIC SOLVENTS.

17.	SN^2 reactions of alkyl halides is a bimolecular reaction which take place through formation of a transition state. The rate of reaction depends on the concentration of alkyl halide andnucleophile.The reaction is favoured by strong nucleophlie in polar aprotic solvents. In which of the following solvents SN^2reaction is more favourable
Answer» `CH_3COOH` `CH_3OH` `CH_3COCH_3` `H_2O` Solution :Polar APROTIC SOLVENT of acetone `H_3C - oversetunderset(\|\|)(O)(C ) - CH_3`

18.	SN^(2) reaction is a bimolecular reaction which takes places by the formation of T.S. Veolcity of the reaction depends on the concentration of the substrate as well as the nucleophile. The reaction is favoureed by strong Nu^(o-) and in the presence of polar aprotic sovlent, optically active halides give. Walken inversion by SN^(2) mechanism. The presence of hero group (atom) at beta-C atom,unsaturation at beta-C and(-overset(O)overset(\|\|)(C)-) group at alpha-C atomn favor SN^(2) mechanism. Allyl halides and benzyl halides give SN^(1) andSN^(2) reactions. Allyl halides alos give SN^(2) mechanism EDG at ortho- and para-postions in benzyl halides favors SN^(1)mechanism, wheras EWG favors SN^(2) mechanism. Which of the following will give SN^(1) reaction?
Answer» All Solution :All, `(a) IMPLIES` Allyk halide, (B) benzyl halide with `EDG`, `(C) implies`benzyl halide with `EDG`

19.	S_N2 reactions are
Answer» Stereospecific but not stereoselective Stereoselective but not stereospecific Stereoselective as WELL as stereospecific NEITHER stereoselective nor stereospecific ANSWER :C

20.	S_(N^(2)) reaction will be fastest in :
Answer» `CH_3Br` `CH_3Cl` `C_(2)H_(2)CL` `(CH_(3))_(2)CH-Cl` Answer :D

21.	SN^(2) reaction is a bimolecular reaction which takes places by the formation of T.S. Veolcity of the reaction depends on the concentration of the substrate as well as the nucleophile. The reaction is favoureed by strong Nu^(o-) and in the presence of polar aprotic sovlent, optically active halides give. Walken inversion by SN^(2) mechanism. The presence of hero group (atom) at beta-C atom,unsaturation at beta-C and(-overset(O)overset(\|\|)(C)-) group at alpha-C atomn favor SN^(2) mechanism. Allyl halides and benzyl halides give SN^(1) andSN^(2) reactions. Allyl halides alos give SN^(2) mechanism EDG at ortho- and para-postions in benzyl halides favors SN^(1)mechanism, wheras EWG favors SN^(2) mechanism. Which of the following will gives SN^(2) mechanism gt
Answer» `ETBR` All Solution :`(a) implies 1^(@) RX, (b) implies 3^(@)`, ALLYL halide `(c) implies allyl halide.

22.	SN^(2) reaction is a bimolecular reaction which takes places by the formation of T.S. Veolcity of the reaction depends on the concentration of the substrate as well as the nucleophile. The reaction is favoureed by strong Nu^(o-) and in the presence of polar aprotic sovlent, optically active halides give. Walken inversion by SN^(2) mechanism. The presence of hero group (atom) at beta-C atom,unsaturation at beta-C and(-overset(O)overset(\|\|)(C)-) group at alpha-C atomn favor SN^(2) mechanism. Allyl halides and benzyl halides give SN^(1) andSN^(2) reactions. Allyl halides alos give SN^(2) mechanism EDG at ortho- and para-postions in benzyl halides favors SN^(1)mechanism, wheras EWG favors SN^(2) mechanism. Which of the following will give Walden inversion ?
Answer» `C_(4)H_(9) - CHD - Br`, All Solution :(a) is only OPTICALLY active, and will have WALDEN inversion.

23.	SN^(2) reaction is a bimolecular reaction which takes places by the formation of T.S. Veolcity of the reaction depends on the concentration of the substrate as well as the nucleophile. The reaction is favoureed by strong Nu^(o-) and in the presence of polar aprotic sovlent, optically active halides give. Walken inversion by SN^(2) mechanism. The presence of hero group (atom) at beta-C atom,unsaturation at beta-C and(-overset(O)overset(\|\|)(C)-) group at alpha-C atomn favor SN^(2) mechanism. Allyl halides and benzyl halides give SN^(1) andSN^(2) reactions. Allyl halides alos give SN^(2) mechanism EDG at ortho- and para-postions in benzyl halides favors SN^(1)mechanism, wheras EWG favors SN^(2) mechanism. Which of the following will give SN^(2) mechanism?
Answer» `MEBR` All Solution :All, `(a) implies 1^(@) RX, (B) implies` Allyl halide, `(C) implies` Benzylhalide.

24.	SN^(2) mechanism proceeds through the formation of
Answer» CARBONIUM ion carbonion T.S. FREE radical Answer :C

25.	S_(N^(2)) reaction are
Answer» stereoselective as WELL as atereopecific stereoselective but not stereospecific stereospecific but not stereoselective Neither stereospecific nor stereoselective Answer :A

26.	S_(N^(2)) mechanism proceeds through the formation of
Answer» CARBONIUM ION TRANSITION STATE Free RADICAL Carbonion Solution :Transition state

27.	S_N2 mechanism is observed in :
Answer» (I)(III)(R) (IV)(iv)(R) (II)(iii)(Q) all Solution :

28.	S_N1 + S_N2 mixed mechanism is observed in the reaction
Answer» <P>(I)(iii)(P) (II)(i)(P) (III)(IV)(Q) (IV)(ii)(S) SOLUTION :

29.	S_N1 reactions occur through the intermediate formation of
Answer» CARBOCATIONS CARBANIONS FREE radicals None of these Answer :A

30.	SN^1reactions never occur on
Answer» `SP^3C - X` `sp^2 C - sp^3C -X` `sp C -X` any of these ANSWER :C

31.	S_(N)1 reactions are accompanied by racemization in optically active halides.
Answer» SOLUTION :In `S_(N)1` reactions, carbocations are the INTERMEDIATES. Since carbocations are planar species, therefore, attack of the nucleophile on them cann occur from both the sides (front and rear) with ALMOST equal ease GIVING a 50:50 mixture of the TWO enantiomers, i.e., a racemix mixture is obtained.

32.	S_(N)1 reaction undergoes in which type of fission ?
Answer» Homolytic fission Heterolytic fission Heterolytic fusion Nuclear fission Solution :Heterolytic fission C - Br bond of `3^(@)` - HALIDE OCCURS in all `S_(N)1` REACTION

33.	S_(N)1 reaction of alkyl halides leads to :
Answer» retentionof CONFIGURATION racemisation INVERSION of configuration NONE of these Answer :B

34.	S_N^1 reaction on optically active substrates mainly gives:
Answer» RETENTION in configuration Inversion in configuration Racemic product No product Answer :C

35.	SN^1 reaction is given by alkylhalide which forms stable carbocation during reaction. The carbonation, has sp^2 hybridisation. In SN^1reaction, the attack of the nucleophile to carbocation inter mediate is from either side. In SN^2reaction the attacking nucleophile attacks from the back leading to the formation of inversion complex. Alcohol reacts with PCI_5to give alkyl chloride byan internal attack of nucleophile with in the molecule. In the following reaction . If R is H - undersetoverset(\|)(D)oversetunderset(\|)(CH_3)(C ) - R - OH underset(Py)overset(SOCl_2)(to) R - Cl + SO_2 + HCl
Answer» There is no CHANGE in CONFIGURATION The configuration is inverted RACEMISATION OCCURS Racemisation with inversion Solution :

36.	SN^(1) reaction is.
Answer» SINGLE STEP REATION a REACTION involving FREE readical intermediate two step reaction two step and reaction intermediate is carbocation Answer :D

37.	S_(N)1 mechanism of alkyl halides is favoured by :
Answer» HIGHER concentration of nucleophile POLAR solvents presence of LESS bulky ALKYL groups strong nucleophiles Answer :B

38.	SN reaction is givenby these compounds, whichhave a nuclophilic group and a good leaving EWG. It should be stable after leaving with bonding pair of overline(e)'s and it should have high polarisability. Nucliphilic aliphatic substituion reaction is mainly of two types SN^(-1) and SN^(2). SN^(-1) mechanism is a two step process. Reaction velocity of SN^(-1) depends only on the concentration of the subtrate. It proceeds via the formation of carbocation, optically active substrate gives (o+) and (o-) froms of the product. In most of the cases, the product usually consists of 5-20% inverted and (95-80%) racemised species. The more stable is the carbocation, the greater is the propotion of racemission. In solvolysis reaction, the more nucleophillic is the solvent, the greater is the proportion of inversion. Which of the following gives SN^(1) reaction?
Answer» `MeBr` All Solution :It is `3^(@) RX` and FORMS stable `PhMe_(2)C^(o+)` ion.

39.	SN reaction is givenby these compounds, whichhave a nuclophilic group and a good leaving EWG. It should be stable after leaving with bonding pair of overline(e)'s and it should have high polarisability. Nucliphilic aliphatic substituion reaction is mainly of two types SN^(-1) and SN^(2). SN^(-1) mechanism is a two step process. Reaction velocity of SN^(-1) depends only on the concentration of the subtrate. It proceeds via the formation of carbocation, optically active substrate gives (o+) and (o-) froms of the product. In most of the cases, the product usually consists of 5-20% inverted and (95-80%) racemised species. The more stable is the carbocation, the greater is the propotion of racemission. In solvolysis reaction, the more nucleophillic is the solvent, the greater is the proportion of inversion. Which of the following will give SN reaction?
Answer» `R-Br` `R-N_(3)` `R-O^(o+)H_(2)` All Solution :All

40.	SN reaction is givenby these compounds, whichhave a nuclophilic group and a good leaving EWG. It should be stable after leaving with bonding pair of overline(e)'s and it should have high polarisability. Nucliphilic aliphatic substituion reaction is mainly of two types SN^(-1) and SN^(2). SN^(-1) mechanism is a two step process. Reaction velocity of SN^(-1) depends only on the concentration of the subtrate. It proceeds via the formation of carbocation, optically active substrate gives (o+) and (o-) froms of the product. In most of the cases, the product usually consists of 5-20% inverted and (95-80%) racemised species. The more stable is the carbocation, the greater is the propotion of racemission. In solvolysis reaction, the more nucleophillic is the solvent, the greater is the proportion of inversion. Fugacity power of which group will be maximum?
Answer» `CH_(3) - O - underset(O)underset(\|\|)overset(O)overset(\|\|)(S)-C_(2)H_(5)` `CH_(3) - O - underset(O)underset(\|\|)overset(O)overset(\|\|)(S)-CH_(3)` `CH_(3) - O - overset(O)overset(\|\|)(C)-CH_(3)` SOLUTION :Stronger the acid or weaker the base, better is the leaving GROUP. In `(C)` due to `-I` effect of THREE `F` atoms, it makes stronger acid. Therfore, the order of leaving group: `(c) gt (B) gt (a) gt (d)`.

41.	Sn is dissolved in excess of NaOH solution, the compound obtained is
Answer» `SN(OH)_(2)` `Na_(2)SnO_(3)` `Na_(2)SnO_(2)` `SnO_(2)` SOLUTION :`Sn+2NaOH+H_(2)O to Na_(2)SnO_(3) +2H_(2)`

42.	S_N1 reaction is favoured by :
Answer» Non POLAR solvents More no of alkyl group on the carbon atom attached to the halogen atom Less NUMBER of GROUPS on the carbon attached to halogen atom None Answer :B

43.	SN1 reaction is fastest in:
Answer» ETHYL chloride Isopropyl chloride t- BUTYL chloride s- butyl chloride Answer :A

44.	Smoke is passed through charged surface before allowing it to come out of chimeys in factories. Assign reason.
Answer»

45.	Smoke has generally blue tinge. It is due to:
Answer» SCATTERING coagukation Brownian motion electro-osmosis Solution :SMOKE is BLUE because of scattering of LIGHT

46.	Smoke is a dispersion of:
Answer» A solid in gas A gas in solid A gas in gas A LIQUID in gas. SOLUTION : A solid in gas

47.	Smoke, cloud and gold sol are respectively
Answer» AEROSOL, Hydosol and Aquasol HYDROSOL, Hydrosol and Hydrosol Aquasol, Aerosol and Hydrosol Aerosol, Aerosol and Hydrosol Answer :D

48.	Smog is :
Answer» NOTHING but BLACK smoke A combination of smoke and fog A liquid particle resulting from vapour condensation A solid particle,e.g.,flyash Answer :B

49.	Smetling is done in
Answer» BLAST furnace Muffle furnace Open-hearth furnance Electric furnace Answer :A

50.	Smog is a common pollutant in places having
Answer» EXCESSIVE `SO_2` in the air Low temperature High temperature Excessive AMMONIA in the air Answer :B