VIT Engineering VIT Engineering Solved Paper-2009

  • question_answer
    One per cent composition of an organic compound A is, carbon: 85.71% and hydrogen 14.29%. Its vapour density is 14. Consider the following reaction sequence \[{{H}_{3}}C-C{{H}_{2}}-C\equiv CH\] Identify , \[{{H}_{2}}C=CH-C\equiv CH\]

    A)  \[HC\equiv C-C{{H}_{2}}-C\equiv CH\]

    B)  \[NaOH\]

    C)  \[{{104}^{o}}40\]

    D)  \[{{103}^{o}}\]

    Correct Answer: B

    Solution :

    \[C=85.71%=\frac{85.71}{12}=7.14;\]     \[\frac{7.14}{7.14}=1\] \[H=14.29%=\frac{14.29}{1}=14.29;\]   \[\frac{14.29}{7.14}=2\] \[\therefore \] Empirical formula \[=C{{H}_{2}}\] and, empirical formula weight \[=12+2=14\] Again, molecular formula weight \[=2\times \] vapour density \[=2\times 14=28\] \[\therefore \] \[n=\frac{28}{14}=2\] \[\therefore \] Molecular formula \[={{(C{{H}_{2}})}_{2}}={{C}_{2}}{{H}_{4}}\] \[\underset{(A)}{\mathop{C{{H}_{2}}=C{{H}_{2}}}}\,+HOCl\xrightarrow{{}}\underset{(B)}{\mathop{\underset{\begin{smallmatrix}  | \\  OH \end{smallmatrix}}{\mathop{C{{H}_{2}}-C{{H}_{2}}-Cl}}\,}}\,\] \[+KCN\xrightarrow{EtOH}\] \[\underset{OH}{\mathop{\underset{|}{\mathop{C{{H}_{2}}-C{{H}_{2}}-CN}}\,}}\,\xrightarrow{{{H}_{3}}{{O}^{+}}}\underset{(C)}{\mathop{\underset{\begin{smallmatrix}  | \\  OH \end{smallmatrix}}{\mathop{C{{H}_{2}}-C{{H}_{2}}-COOH}}\,}}\,\]


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