Question

When sugar is added to the sulphuric acid, we get a very pure form of:
A. Carbon
B. Oxygen
C. Water
D. Hydrogen

Answer 1

Carbon snake is a demonstration of dehydration of sugar by concentrated sulphuric acid. With the concentrated sulphuric acid we use granulated table sugar that is sucrose which performs a degradation reaction which changes its form to a black solid liquid mixture. The carbon sugar snake is the product which is formed by three reactions that are dependent on each other on the basis of heat.

Complete step by step answer:
As we know sulphuric acid is a very strong dehydrating agent. Sulphuric acid dehydrates the compound by removing water from it. This can be easily seen in charring action on carbohydrates.
The equation for the same is provided below:
${{C}_{12}}{{H}_{22}}{{O}_{11}}\xrightarrow{conc.sulphuric\; acid}12C+11{{H}_{2}}O$
The final products are carbon, water vapour, and sulphur dioxide gas.

Hence the option A is the correct one.

Additional Information:
Sulphuric acid is also called oil of vitriol, or hydrogen sulphate. It is a dense , oily, corrosive liquid. This acid is used in the manufacture of many things such as fertilizers, petroleum refining, pigments, dyes, explosives and detergents. The most common application of sulphuric acid is the electrolyte in lead acid storage batteries. The pure sulphuric acid has a specific gravity of 1.830 at 25degree celsius. It freezes at 10.37 degree celsius. The reason why pure anhydrous sulphuric acid does not exist in nature is because of the affinity of water towards it. Even volcanic activity produces sulphuric acid. In aqueous solution it ionizes completely to form hydronium ions and hydrogen sulphate ions. The term fuming sulphuric acid or oleum is applied to solutions of sulphur trioxide in 100 percent sulphuric acid.

Note: Students should remember the properties of sulphuric acid such as dehydrating properties, etc. they should know the reactions to gain more marks. Students should remember those three reactions of carbon sugar snake in which sugar burns in presence of oxygen. This produces carbon dioxide, and water vapor.