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Questions
With the help of an appropriate example, justify that some of the chemical reactions are determined by the evolution of a gas.
Give a chemical equation for the reaction involved in the above case.
Give one example of a chemical reaction characterised by the evolution of a gas.
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Solution
When zinc granules react with dilute sulphuric acid in a flask, hydrogen gas evolves, and zinc sulphate solution is formed.
\[\ce{Zn(s) + H2SO4(aq)->ZnSO4(s) + H2(g)}\]
Notes
Students should refer to the answer according to their questions.
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