Chemistry
(a) Name the chemicals required to prepare hydrogen gas in the laboratory.
(b) Give a balanced chemical equation for the reaction.
(c) Draw a neat and well-labelled diagram for the laboratory preparation of hydrogen.
(d) How is hydrogen gas collected? Why?
(e) Give one chemical test for hydrogen. Why?
Answer
(a) Granulated zinc and dilute hydrochloric acid are the chemicals required to prepare hydrogen gas in the laboratory.
(b) Zn + 2HCl ⟶ ZnCl2 + H2 (g)
(c) Below diagram shows the laboratory preparation of Hydrogen gas:
(d) Hydrogen gas is collected by downward displacement of water as it is sparingly soluble in water. Though hydrogen gas is lighter than air, it is not collected by downward displacement of air as a mixture of hydrogen and air can lead to an explosion.
(e) Hydrogen gas burns in air with a pop sound. This is because of the presence of impurities in it. This method is widely used as a test to identify hydrogen.
Related Questions
State four uses of hydrogen.
Give three differences between Cathode and anode.
Give three differences between Cation and anion.
The diagram given below shows electrolysis of water. Answer the following questions :
(a) Label A, B, C, D, E and F.
(b) Why is acidulated water used ?
(c) What is the ratio by volume for the gases collected ?