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?
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.
Related Questions
Give reasons for the following:
(a) Hydrogen can be used as a fuel.
(b) Though hydrogen is lighter than air it cannot be collected by downward displacement of air.
(c) A pop sound is produced when hydrogen gas is burnt.
(d) Helium has replaced hydrogen in weather observation balloons.
(e) Nitric acid is not used for the preparation of hydrogen gas.
Name the following:
(a) Two metals which give hydrogen with cold water.
(b) A metal which liberates hydrogen only when steam is passed over red hot metal.
(c) The process in which oxygen is added or hydrogen is removed.
(d) A metallic oxide which can be reduced into metal by hydrogen.
How would you show that hydrogen:
(a) is a non-supporter of combustion?
(b) is lighter than air?
Hydrogen is a good reducing agent. What do you understand by the above statement? Explain with the help of copper oxide as an example.