2
Thistle funnel 'Y
Hydrogen
granulated zinc.
3.
Gas jar
granules
DII. HCI
the apparatus is allowed to escape.
Name a gas other than hydrogen collected by the
same method.
112
Q.6 The diagram represents the preparation & collection of hydrogen by a standard laboratory methods
State what is added through the thistle funnel
State what difference will be seen il pure in
added in the distillation flask 'X instead
Name a solution which absorbs the impurity - HS
State why hydrogen is collected after all the
Answers
Answer:
Explanation:
Laboratory Preparation of Hydrogen Gas
The laboratory preparation of hydrogen gas usually involves the action of dilute sulphuric acid or dilute hydrochloric acid on zinc granules. Granulated zinc is ideal for the preparation of hydrogen gas in chemical laboratories because it usually contains a small amount of copper, which has the ability to act as a catalyst to the associated chemical reaction and, therefore, increase the rate of the chemical reaction without actually participating in it. An experimental procedure for the laboratory preparation of hydrogen gas is provided below.
Procedure for the Laboratory Preparation of Hydrogen Gas
Step 1: Take a few grams of zinc granules and place them in a 500 mL flask.
Step 2: With the help of a thistle funnel, add dilute hydrochloric acid to the zinc granules. If hydrochloric acid isn’t available, dilute sulphuric acid can be used as an alternative.
Step 3: Hydrogen gas will be automatically collected with the help of a delivery tube via the downward displacement of water. This can be explained by the fact that hydrogen gas is lighter than water.
The setup for the laboratory preparation of hydrogen gas is illustrated below.
Laboratory Preparation of Hydrogen Gas
The chemical reactions that take place during the preparation of hydrogen gas via this method are listed below.
General Format: Metal + Dilute Acid → Salt of Metal & Acid + Hydrogen
With Hydrochloric Acid: Zn + 2HCl → ZnCl2 + H2
With Sulphuric Acid: Zn + H2SO4 → ZnSO4 + H2
Finally, the hydrogen gas can be collected by the downward displacement of water.
Precautions to be Taken While Preparing Hydrogen Gas in the Laboratory
Before collecting the hydrogen gas with the help of the apparatus, precautions must be taken in order to ensure that all the air inside the apparatus has been displaced. This is because hydrogen gas reacts explosively with air.
Characteristics and Uses of Hydrogen Gas
Hydrogen gas is a colourless gas which does not have any distinct odour. This gas is sparingly soluble in water. The solubility of this gas in water is not affected too much by any changes in temperature. Some uses of hydrogen gas are listed below.
This gas is used to fill many balloons and airships.
It is also used for the hardening of animal oils and certain vegetable oils.
Hydrogen gas is widely used as a fuel in oxy-hydrogen blow pipes.