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896 mL of a hydrocarbon 'A' having carbon 87.80 % and hydrogen 12.19% weighs 3.28 g at STP. Hydrogenation of 'A' gives 2-methylpentane. Also 'A' on hydration in the presence of H_(2)SO_(4) and HgSO_(4) gives a ketone 'B' having molecular formula C_(6)H_(12)O. The ketone 'B' gives a positive iodoform test. Find the structure of 'A' and give the reaction involved. |
| Answer» <html><body><p></p>Solution :`"896 <a href="https://interviewquestions.tuteehub.com/tag/ml-548251" style="font-weight:bold;" target="_blank" title="Click to know more about ML">ML</a> of" C_(x)H_(y) (A) "weigh"=3.28 g` <br/> `"22400 mL of" C_(x)H_(y) (A) "weigh"=(3.28)/(896) xx 22400` <br/> `=82 g mo1^(-1)` <br/> `:. "Molecular mass of " C_(x)H_(y)=82 g mo1^(-1)` <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/MOD_SPJ_CHE_XI_P2_C13_SLV_044_S01.png" width="80%"/> <br/> `"Empirical formula of A"=C_(3)H_(5)` <br/> `"Empirical formula mass"= 3 xx <a href="https://interviewquestions.tuteehub.com/tag/12-269062" style="font-weight:bold;" target="_blank" title="Click to know more about 12">12</a> +5 xx 1=41` <br/> `n=("Molecular formula mass")/("Empirical formula mass")=(82)/(41)=2` <br/> `:. "Molecular formula" =(C_(3)H_(5))_(2)=C_(6)H_(10)` <br/> Now `underset((A))(C_(6)H_(10)) overset("2 mole")to "2-Methylpentane" CH_(3)-underset(CH_(3))underset(|)CH-CH_(2)CH_(2)-CH_(3)` <br/> The molecular has a chain of 5 carbon atoms with a <a href="https://interviewquestions.tuteehub.com/tag/methyl-1095247" style="font-weight:bold;" target="_blank" title="Click to know more about METHYL">METHYL</a> group at the second carbon atom. Since A adds a molecule of `H_(2)O` in the presence of `Hg^(2+)` and `H^(+)` to give a ketone (B), it should be an alkyne. Two possible structures of .A. are <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/MOD_SPJ_CHE_XI_P2_C13_SLV_044_S02.png" width="80%"/> <br/> Since the compounds B does not react with `AgNO_(3)` solution, the triple bond is not terminal and therefore, structure (I) is the <a href="https://interviewquestions.tuteehub.com/tag/correct-409949" style="font-weight:bold;" target="_blank" title="Click to know more about CORRECT">CORRECT</a> structure. <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/MOD_SPJ_CHE_XI_P2_C13_SLV_044_S03.png" width="80%"/></body></html> | |