Question

26 .The formulae of four organic compounds are given below:

A B C D

C2H4 CH3COOH C2H5OH C2H6

(i) Which one of these compounds A, B, C or D is a saturated hydrocarbon?

(ii) Identify the organic acid and give its structural formula.

(iii) Which of the above compounds when heated at 443K in the presence of

concentrated H2SO4 forms ethene as the major product? What is the role played by

concentrated H2SO4 in this reaction? Also write the chemical equation involved.

(iv) Give a chemical equation when B and C react with each other in presence of

concentrated H2SO4. Name the major product formed and mention one of its

important use. ​

Answer 1

An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH. Sulfonic acids, containing the group –SO2OH, are relatively stronger acids. Alcohols, with –OH, can act as acids but they are usually very weak. The relative stability of the conjugate base of the acid determines its acidity. Other groups can also confer acidity, usually weakly: the thiol group –SH, the enol group, and the phenol group. In biological systems, organic compounds containing these groups are generally referred to as organic acids.

Answer 2

(i) D is a the saturated hydrocarbon .

(ii) B ( acetic acid ) is the organic acid . Its structural formula is CH₃COOH .

(iii) C ( Ethyl alcohol ) produce ethene as major product when heated at 443 K in presence of  concentrated H$_{2}$SO$_{4}$ .

C$_{2}$H$_{5}$OH  -------> CH₃COOH ( at 443 K in presence of conc. H$_{2}$SO$_{4}$ )

(iv) Chemical equation is --

  C$_{2}$H$_{5}$OH + CH₃COOH →  CH$_{3}$COOC$_{2}$H$_{5}$ + H$_{2}$O

Major product is Ester ( Ethyl ethanoate ) . It is an organic solvent .