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896 mL vapour of a hydrocarbon 'A' having carbon 87.80% and hydrogen 12.19% weighs 3.28 gat STP. Hydrogenation of 'A' gives 2-methyl pentane. Also 'A' on hydration in the presence of H_(2)SO_(4) and HgSO_(4) gives a ketone 'B' moelcular formula C_(6)H_(12)O. The ketone 'B' gives a positive iodoformtest. Find the structure of 'A' and give the reactions involved. |
| Answer» <html><body><p></p><a href="https://interviewquestions.tuteehub.com/tag/solution-25781" style="font-weight:bold;" target="_blank" title="Click to know more about SOLUTION">SOLUTION</a> :To calculate molar <a href="https://interviewquestions.tuteehub.com/tag/mass-1088425" style="font-weight:bold;" target="_blank" title="Click to know more about MASS">MASS</a> of hydrocarbon .A. it is given that 896 ml of Hydrocarbon .A. `C_(<a href="https://interviewquestions.tuteehub.com/tag/x-746616" style="font-weight:bold;" target="_blank" title="Click to know more about X">X</a>)H_(y)` Weighs 3.28 gat STP. <br/> 22400 ml of has `AC_(x)H_(y)` mass `= 3.28 xx 22400` ml/896ml = 831 g/<a href="https://interviewquestions.tuteehub.com/tag/mol-1100196" style="font-weight:bold;" target="_blank" title="Click to know more about MOL">MOL</a>. Hence, the molar mas of A = 831 g mol. <br/> <img src="https://doubtnut-static.s.llnwi.net/static/physics_images/KPK_AIO_CHE_XI_P2_C13_E04_049_S01.png" width="80%"/> <br/> Thus, empirical formula `=C_(3)H_(5)` <br/> Empirical formula weight `= 3 xx 12= 36 + 5 = 41`. <br/> Molecular formula = (Empirical formula)n<br/> n = Mol. mass/Empirical mass = 831/41 = 2.02. <br/> Molecular formula `= [C_(3)H_(5)]_(2) = C_(6)H_(10)` <br/> To detremine the structure of (A) and (B) : `C_(6)H_(10)` on hydrogenation with 2 moles of `H_(2)` gives `C_(6)H_(12)` and structure is 2-methylpentane. (A) on hydration in presence of dil. `H = H_(2)SO_(4)` and `HgSO_(4)` gives `C_(6)H_(12)O` which gives Iodoformtest positive. Hence, structure of `A = (CH_(3))_(2)<a href="https://interviewquestions.tuteehub.com/tag/ch-913588" style="font-weight:bold;" target="_blank" title="Click to know more about CH">CH</a>-CH-C=CH` (4-methylpentlyne) and (B) is 4-methylpentanone-2.</body></html> | |