Question

(a) Give a chemical test to distinguish between saturated and unsaturated hydrocarbon.

(b) Name the products formed when ethane burns in air. Write the balanced chemical equation for the reaction showing the types of energies liberated.

(c) Why is reaction between methane and chlorine in the presence of sunlight considered a substitution reaction?​

Answer 1

Answer :

a. Chemical test to distinguish saturated and unsaturated hydrocarbons :-

Pass the vapours of the samples of saturated and unsaturated hydrocarbons into bromine water taken in two separate test tubes. The one which discharges the colour of bromine water is that of unsaturated hydrocarbon and rest of the other represents saturated hydrocarbon.

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b. On burning ethane in air, the products obtained are carbon dioxide and water, with heat and light.

• $\rm{2C_2H_6(g)+7O_2(g)\longrightarrow{}4CO_2(g)+6H_2O(l)+Heat+Light}$

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c. It is considered a substitution reaction because the hydrogen atoms of methane $\rm{(CH_4)}$ are replaced/substituted by chlorine atoms one by one successively.