Question

(a) What happens when propanoic acid is warmed with methanol in the presence of a few drops of
concentrated sulphuric acid ? Write equation of the reaction involved.
(b) What change will you observe if you test soap solution with a litmus paper (red and blue) ? Give reason for your observation.
(c) What is meant by denatured alcohol ? What is the need to denature alcohol ?

Lakhmir Singh Chemistry Class 10

Answer 1

Answer:

a)In the presence of concentrated Sulphuric acid , Propanoic acid will react with Methanol to give esters.

CH3CH2COOH + CH3OH -> CH3CH2COOCH3 + H20

Propanoic            Methanol    Methypropanoate

 acid

b) When a soap solution is being tested with red litmus paper it turns into blue due to its basic nature and no change is observed in case of blue litmus paper.

c) By addition of substances like methanol, copper sulphate, pyridine, in ethanol it is made undrinkable which is called denaturation  of alcohol.  To prevent the drinking alcohol from being mishandled or misused it is being denatured.