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प्रश्न
Give reason for the following:
When concentrated sulphuric acid is added to sugar/glucose, a black mass is left behind.
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उत्तर
The carbohydrates contain carbon, hydrogen and oxygen. The hydrogen and oxygen are always in ratio of 2:1 which is absorbed by acid in the form of water, thus leaving carbon behind. This is also called as charring.
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संबंधित प्रश्न
Give balanced chemical equations for the action of sulphuric acid on the following:
Potassium hydrogen carbonate.
Name the products formed when hot and concentrated sulphuric acid reacts with Carbon.
Define the following term : Hygroscopic substance
What do you see when concentrated sulphuric acid is added to copper sulphate-5-water ( You are not required to say what is happing, nor is it necessary to name the products.)
Copy and complete the following table.
Column 3 has the names of gases to be prepared using the substance you enter in column 1, along with dilute or concentrated sulphuric acid, as indicated in column 2.
| Column 1 | Column 2 | Column 3 |
| Substance reacted with acid | Dilute or concentrated sulphuric acid | Gas |
| Hydrogen | ||
| Carbon dioxide | ||
| Only chlorine |
Write the equation for the laboratory preparation of :
(i) Sodium sulphate using dilute sulphuric acid.
(ii) Lead sulphate using dilute sulphuric acid.
Write the equation for the laboratory preparation of the following salts, using sulphuric acid.
Lead sulphate from lead nitrate.
Name the gas evolved in following case:
The gas produced by the action of concentrated sulphuric acid on sodium chloride.
State your observation for the following case:
Paper soaked in potassium permanganate solution is introduced into a gas jar of sulphur dioxide.
State your observation of the following case:
When dilute hydrochloric acid is added to sodium carbonate crystals.
The salt is formed when concentrated sulphuric acid reacts with KNO3 above 200°C.
