Question

A compound X on heating with an excess of conc. sulphuric acid at 443 K gives a saturated 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 formulation of Y and also write the role of sulphuric acid in the reaction.

Answer 1

Hint: In the reaction converting X to Y, sulfuric acid is used as a dehydrating agent which will take the water molecule from the compound X. Dehydration of X into Y is an elimination reaction which gives Z which is the lightest gas.

Complete step by step solution:
-According to the question,

$\begin{align}
  & X\xrightarrow[443K]{conc.{{H}_{2}}S{{O}_{4}}}Y(\text{unsaturated compound)} \\
 & \\
\end{align}$
$X\xrightarrow{Na}Z(\text{colourless gas)}$

-Sulfuric acid is a clear, colourless, oily, odourless, and water-soluble chemical compound. It is a sulfur oxoacid that consists of two oxo and two hydroxyl groups joined via a covalent bond with the central sulfur atom.

-Assuming the compound X as alcohol, then compound Y and Z will be alkene and hydrogen respectively.

-Let us suppose that X is ethanol, so the ethanol on reacting with sulfuric acid will lose water molecule as sulfuric acid acts as a dehydrating agent, so the Y will be ethene.
${{C}_{2}}{{H}_{5}}OH(X)\xrightarrow[443K]{conc.{{H}_{2}}S{{O}_{4}}}{{C}_{2}}{{H}_{4}}(Y)$

-Now, compound X, that is ethanol on further reacting with sodium metal gives the compound Z which is a colourless gas and whose reaction can be written as-
$2{{C}_{2}}{{H}_{5}}OH(X)\xrightarrow{Na}2{{C}_{2}}{{H}_{5}}ONa+{{H}_{2}}(Z)$

So, the compounds X, Y, and Z are ethanol, ethene, and hydrogen gas respectively.

Note: Sulfuric acid is produced in large amounts throughout the world which is the indicator of being a very important commodity chemical for various industries. About 60% of the total sulfuric acid produced nationwide is used for preparing fertilizers especially superphosphates, ammonium phosphate, and ammonium sulfates. About 20% of the total nationwide production is used in the chemical industry for the preparations of detergents, synthetic resins, dyestuffs, pharmaceuticals, petroleum catalysts, insecticides, and anti-freezing agents. About 6% of the total nationwide production of the sulfuric acid is related to pigments and includes paints, enamels, printing inks, coated fabrics, and paper. The rest part of the produced sulfuric acid is used as the production of explosives, cellophane, acetate and viscose textiles, lubricants, non-ferrous metals, and batteries.