Chemistry
The diagram represents the preparation & collection of hydrogen by a standard laboratory method.
- State what is added through the thistle funnel 'Y'.
- State what difference will be seen if pure zinc is added in the distillation flask 'X' instead of granulated zinc.
- Name a solution which absorbs the impurity – H2S.
- State why hydrogen is collected after all the air in the apparatus is allowed to escape.
- Name a gas other than hydrogen collected by the same method.
Answer
- Dilute hydrochloric acid [HCl]
- When pure zinc is added in the distillation flask 'X' instead of granulated zinc, the rate of production of H2 is slow. Granulated zinc is commercial zinc obtained from molten zinc, it contains traces of impurities which has a slight catalyzing effect on the reaction.
- Lead nitrate Pb(NO3)2 solution absorbs H2S
- Hydrogen is collected after all the air in the apparatus is allowed to escape as hydrogen forms an explosive mixture with air.
- Oxygen gas.
Related Questions
Give reasons for the following:
Hydrogen is collected by the downward displacement of water and not air even though it is lighter than air.
Give reasons for the following:
A mixture of hydrogen and chlorine can be separated by passage through a porous pot.
Name the following
- A metal below iron but above copper in the activity series of metals which has no reaction with water.
- A metal which cannot be used for the preparation of hydrogen using dilute acids.
- The salt formed when aluminium reacts with potassium hydroxide, during the preparation of hydrogen from alkalis.
- A gaseous reducing agent which is basic in nature.
- A compound formed between hydrogen and an element from group 17 [VIIA] – period 3.
Select the correct answer from the symbols in bracket.
- The element placed below hydrogen in group 1 [IA]. [Na, Li, K, F],
- The element other than hydrogen, which forms a molecule containing a single covalent bond. [Cl, N, O]
- The element, which like hydrogen has one valence electron. [He, Na, F, O]
- The element, which like hydrogen is a strong reducing agent. [Pb, Na, S, Cl]
- The element which forms a diatomic molecule. [C, Br, S, P]