question_answer

A compound 'X' on heating with excess cone. sulphuric acid at 443 K gives an unsaturated compound 'Y'. 'X' also reacts with sodium metal to evolve a colourless gas 'Z'. Identify 'X' 'Y' and 'Z'. Write the equation of the chemical reaction of formation of 'Y' and also write the role of sulphuric acid in the reaction.

Answer:

\[\text{Compound }X\xrightarrow[\begin{smallmatrix}  \text{excess conc}\text{.} \\  {{H}_{2}}S{{O}_{4}}  \\  \text{  at 443K} \end{smallmatrix}]{\text{Heating}}\text{Unsaturated compound}\mathrm{ }Y\]

\[\underset{\text{Ethanol}}{\mathop{C{{H}_{3}}-C{{H}_{2}}OH}}\,\xrightarrow[443K]{\text{Conc}\text{. }{{H}_{2}}S{{O}_{4}}}\underset{\text{Ethene}}{\mathop{C{{H}_{2}}=C{{H}_{2}}}}\,+\underset{\text{Water}}{\mathop{{{H}_{2}}O}}\,\]

\[X=C{{H}_{3}}C{{H}_{2}}OH-ethanol\]

\[Y=C{{H}_{2}}=C{{H}_{2}}-ethene\]

\[C{{H}_{3}}C{{H}_{2}}OH+Na\to C{{H}_{3}}C{{H}_{2}}ONa+{{H}_{2}}\]

Z = Hydrogen gas

Here concentrated sulphuric acid act as a dehydrating agent, it removes water molecule from ethanol