Question

s Electrophilic species in nitration of benzene is or in the HNO) and 1,50 the tack on ting is made by LA NOS MO t o wn IC NO3- IDIMO [6] Which of the following organic compound with molecules forme in the IH NMR spectrum? TA2. 2-dichloropropane B. 2-dichlarga C]1,3-dichloropropane JULI-dichlorogene s In 'H NMR Spectru, protons of benene are highly deshielded and appear in the LAJ 52.0 to 8 4.0 6601575 C 80 to 820 TD Nethew A fure hood is used: [A] For conducting reactions that may result in an explosion [C] To control exposure to hazardous liquids and pases 1B For disposal of toxic liquids and DW the way [9] Which gives a meta nitro compound as the main product up acid mixture? with ** ca oho BB DD LALA ICC [10] The test which is used to distinguish between TA Lucas Test FC Benedicts test Blodeon Baye's test True False 0.11-20 (11) In 'HNMR the area under each peak is proportional to the s [True/False) et of die [12) Tetramethylsilane compound is used as NMR reference in Noclear Magnetic Rese Spectroscopy (True False] [13) The 'H NMR spectrum of CHOCHCICH CI will exhibit: A three pretendohet proton singlet and a two profon doublet. (True False) [14] The unit of chemical shift in NMR spectroscopy is parts per million (ppm) (Truelt [15] "SE stands for bimolecular electrophilic substitution reaction [True False [16] All the hydrogen in tetramethylsilane has the same chemical shift. (True False

Answer 1

Answer IST Electrophilic species in nitration of benzene u or the nitreation of benzene with concentreated HNO3 and H₂SO4 the attack on being is made made by [B] No2t TN > H₂O +0=N=0 (nitro- nium een C. H₂SO4 L ion) (6] Given formula is C₂ H₂ Cl. The condition is that we obserie a single i peak in 'H-NMR spectrum which would be possible only if we have an equivalent environment for all the protons upon investigating the options, the stocucture that agrues to the above condition es. TA] 2,2-dichloro preopane He H. H-e - e - Ho here we have a plane of " . I l symmetry passing a through H e H the ce-atoms bearing C-atom. the ce-atoms bearing a Also the pecotons at terminal @-at ons have same electromagnetic environment, this gives. a single peak signal

2 In HNMR spectra, protons of benzene are in and appear the highly deshielded region. [B] 86.0 to 87.5. This is due to ring current that is gene y the <- clectuons which Onduce an additional magnetic field aligned along the extern fied thereby the nuclei are deshielded and resonates at a higher frequency circulating t-election creating ering current. » Induced field near the deshieldeal protons [8] A fume hoool is used-> [B] for disposal of tox's liquids and gases: [9] meta - riteco compound es obeained as a majose produce for (c) Lieuzi ketone Where the estern geroon engroup has an electron with drawing effect and dwring sesonance the election density is over the meta position: oy me ore, O H NO2 CH3. Opeiko H Non cunstable) meta of the of me TH ETNO of the OBH ne o TH NOZ og mee oor me H NO2 4 No2 HNO2 cunstable)

perimarey [A] Lucas [10] The best used to distinguish secondary and tertiary alcohol is test The neagent used is Anh. ZnCl2 in conc. Hee. Positive test és éndicated by change in appearance of the solution from clear to inclicating formation of chlomoalkane by replacement of hydroxyl gecoup. turbid indicat celear) ROH + Hee R ce + H₂O Ceurbid) It follows SNL pathway. Type of alcohol Appearance of turbidity primary - no visible layer at (least stable - croom temperature cabocation) secondary - appearance of oily eager (moderately in 3-5 minutes stable Carbocation immediate appearance of turbidity Cmost stable carbocation) tertiary

[11] False proportional The area under the peak is to the number of protons. eg Cliyetly Clz. SHa vappon Ethya 1.4 ppm 4 og 8(ppm) internal [12] True. Tetecamethye silane (TMS) is used as an inert, point so easily isolated y standard in NMR beause it is low botling point so easily eso and the protons are highly shielded due to very less difference in electronegativity of so e bond an CH3 si CH₂ CTMS) CHI ettz [13) * False Multipucity es governed by anty perle swthere n no. of neighbouring preston. Considering the structure, considering the he He de ce 1 1 o

we obserwe; (3H, s) corresponding to Ha ;m = 0 (1 Hyd) corresponding to Hb; n = 2 (21 d) corresponding to He: n=1 [14] True. The mathematical formula of chemical shift is, 8 = observed frequency CH4) x 106 operating frequency eg. obs. freeg..= 60Hz офоrе tv kan. = 60Hнз 8 = 60x100 = 1 ppm. 60x106 [15 ] False SE represents unimolecular electrophilic seebstitution reaction [16 ] Tome In teteeamethyl silane, the environment around each proton es same so they will have same chemical shift values.