describe along with chemical equations what happens when: i) Ethane react with bromine water. ii) ethanol burns in air and iii) ethanoic acid reacts with ethanol in the presence of sulphuric acid
Answers
Explanation:
1. Ethane does not react with bromine water. Ethene is an unsaturated compound.it has one double bond. When Bromine water(brown in colour) is added to ethene it reacts with ethene to form a new compound 1,2 dibromoethane which is colourless.The colour of bromine water is gone now.
Generally bromine water is decolourised by all the compounds that contain double or triple bond.
Ethane is a saturated compound with no multiple bond hence does not decolourise bromine water.
2. When ethanol is burnt, it reacts with oxygen and produces water and carbon dioxide. The chemical equation of the combustion of ethanol is: The combustion of ethanol is an exothermic reaction. ... In summary, when ethanol burns, it reacts with oxygen to produce carbon dioxide, water and heat.
3. Ethanoic acid reacts with ethanol in the presence of concentrated sulphuric acid as a catalyst to produce the ester, ethyl ethanoate. The reactionis slow and reversible. To reduce the chances of the reverse reactionhappening, the ester is distilled off as soon as it is formed.
C2H5OH +CH3COOH------> CH3COOC2H5
+H2O
To describe the following reactions with chemical equations :
(i) Reaction of ethane with bromine water :
• Ethane does not react with bromine water.
• Bromine water is a brown coloured mixture of bromine in water. It reacts only with unsaturated compounds containing double bonds and triple bonds.
• Ethane is a saturated compound containing only single bonds between C and H. Therefore, the reaction of ethane with bromine water does not take place.
• This can be identified by the fact that the brown colour of bromine water remains as it is and does not become colourless, unlike in unsaturated compounds.
• The reaction for the same can be represented as below :
C₂H₆ + Br₂ (brown) → No reaction
(ii) Burning of ethanol in air -
• Ethanol is a hydrocarbon made of carbon and hydrogen, represented by the chemical formula C2H5OH.
• All hydrocarbons on burning in air produce carbon dioxide and water as the products.
• Therefore, when ethanol burns in air, it produces carbon dioxide and water as the products.
• This reaction is called a combustion reaction, as it takes place in air, i.e. in the presence of oxygen.
• The chemical equation for the burning of ethanol in air can be shown as follows :
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
(iii) Reaction of ethanoic acid with ethanol in the presence of sulphuric acid :
• The reaction of an acid (RCOOH) with an alcohol (R'OH) in the presence of sulphuric acid produces an ester of the form (RCOOR').
• Sulphuric acid is used as a dehydrating agent in the reaction, whose role is to remove the water molecule formed in the reaction, so that it does not combine with the ester formed in the reaction to give back the acid and the alcohol.
• Therefore, the reaction of ethanoic acid with ethanol in the presence of sulphuric acid forms the ester, ethyl ethanoate.
• The reaction can be chemically represented as follows :
CH₃COOH + C₂H₅OH + H₂SO₄ ⇄ CH₃COOC₂H₅ (ethyl ethanoate) + H₂O