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प्रश्न
Esters are sweet-smelling substances and are used in making perfumes. Describe an activity for the preparation of an ester with the help of a well labelled diagram. Write an equation for the chemical reaction involved in the formation of the ester. Also write the names of all the substances involved in the process of esterification.
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उत्तर
Esters are sweet-smelling substances which are used to make perfumes. The process in which a carboxylic acid reacts with an alcohol to form an ester is called esterification.
An ester is formed when ethanol (alcohol) reacts with ethanoic acid, on heating, in the presence of a few drops of concentrated sulphuric acid. The name of the ester formed is ethyl ethanoate.
Let's prepare an ester.
(1) In a test tube, take 1 ml of ethanoic acid and add some ethanol to it along with a few drops of concentrated sulphuric acid.
(2) Warm the test tube in a beaker, containing hot water, for 5 minutes.
(3) Take about 50 ml of water in another beaker and pour the contents of the test tube into it. When you smell it, a sweet fragrance is obtained indicating the formation of an ester.
The diagrammatic representation of the above process is as follows:
The chemical equation involved in the formation of ester is as follows:
`CH_3 COOH + C_2 H_5 OH` 
`CH_3 COOC_2 H_5 + H_2 O`
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संबंधित प्रश्न
While studying saponification reaction, a student measures the temperature of the reaction mixture and also finds its nature using blue/red litmus paper. On the basis of his observations the correct conclusion would be
(A) the reaction is exothermic and the reaction mixture is acidic.
(B) the reaction is endothermic and the reaction mixture is acidic.
(C) the reaction is endothermic and the reaction mixture is basic.
(D) the reaction is exothermic and the reaction mixture is basic.
How esters are prepared ?
List two uses of esters.
Name the following:
The distinctive reaction that takes place when ethanol is treated with acetic acid.
Draw the structures for the following compounds of Propanoic acid.
What happens when ethanoic acid reacts with sodium hydroxide? Write equation of the reaction involved.
State any two uses of esters.
An organic compound A (molecular formula C2H4O2) reacts with Na metal to form a compound B and evolves a gas which burns with a pop sound. Compound A on treatment with an alcohol C in the presence of a little of concentrated sulphuric acid forms a sweet-smelling compound D (molecular formula C3H6O2). Compound D on treatment with NaOH solution gives back B and C. Identify A, B, C and
A student puts a drop of acetic acid first on a blue litmus paper and then on a red litmus paper. He would observe that
(A) the red litmus paper turns colourless and there is no change in the blue litmus paper.
(B) the red litmus paper turns blue and the blue litmus paper turns red.
(C) there is no change in the red litmus paper and the blue litmus paper turns red.
(D) there is no change in the blue litmus paper and the red litmus paper turns blue.
A student takes 2 mL acetic acid in a dry test tube and adds a pinch of sodium hydrogen carbonate to it. He makes the following observations:
I. A colourless and odourless gas evolves with a brisk effervescence.
II. The gas turns lime water milky when passed through it.
III. The gas burns with an explosion when a burning splinter is brought near it.
IV. The gas extinguishes the burning splinter that is brought near it.
The correct observations are:
(A) I, II, and III
(B) II, III and IV
(C) III, IV and I
(D) IV, I and II
State how the following conversions can be carried out:
Ethene to Ethyl alcohol.
Identify the term or substance based on the descriptions given below:
Ice like crystals formed on cooling an organic acid sufficiently.
Write the answers to the questions by observing the following figure.
- Write the chemical reaction shown in the figure above in the form of a balanced equation.
- Write the name of the gas coming out of the large test tube in the above chemical reaction.
- Why do small bubbles appear in the small test tube?
- What is the change in colour of lime water?
Vinegar is a solution of ______.
Which of the following substance produces brisk effervescence with baking soda solution?
In the presence of the acid catalyst, ethanoic acid reacts with ethanol and ______ ester is produced.
Bubbles are seen in the test tube during the preparation of lime water.
Write an equation showing saponification.
A spatula full of sodium carbonate is taken in a test tube and 2 mL of dilute ethanoic acid is added to it.
Suggest a method of testing the gas liberated in the reaction.
Give the balanced chemical equation of the following reaction:
Neutralization of NaOH with ethanoic acid.
