Chem Notes Chap 13

                                                             Important Questions

Q1 Define carboxylic acids. give their Classification.

Ans The organic compounds containing the carboxyl group as a functionality are called carboxylic acid. the group is itself combination of carbonyl group (>C=O) and hydroxyl group (OH) Carboxylic acid may be aliphatic or aromatic depending upon whether -COOH group is attached with an alkyl or aryl group.

               Aliphatic Carboxylic acid R-COOH                 CH3COOH  Acetic acid 

            Aromatic Carboxylic acid     Ar-COOH             C6H5COOH Benzoic acid

Q2 What are fatty acids ? Give their examples 

Ans The aliphatic monocarboxylic acids are called the fatty acids because they higher members of this series such as Palmitic acid ( C15H31COCOH)Stearic acid are obtained by the hydrolysis of fats and oils.

Q3 Discuss the reactivity of Carboxyl group. Also write down the reactions of carboxylic acids.

Ans : The caboxylic group displays the chemistry of both carbonyl as wellas the hydroxyl groups. In most of the reactions the carboxylic acids the carboxyl group is retained however the reactivity of these molecules is aconsequence of presence of carbonyl group.

                        Reactions of caboxylic Acids :

                    Reaction in which H-atom of carboxyl group is involed.

                   Reactions in which -OH group is involed

                   Reaction in which Carboxyl group is involed.

Q4 Write four uses acetic acid. 

Ans Acetic acid is used :

As a coagulant for latex in rubber industry

In the manufacture of plastics like Polyacetate  rayon and silk.

In medicines as local irritant 

In the manufacture of pickles

In the manufacture of many organic compound like acetone acetates and easter

Q5 What are Esters ? Ester have characteristic smell Write names of ester used as artificial flavours.

Ans The derivatives of carboxylic acid having -COOR group as a functional group are called Ester. Ester have fruity smell are used as artificial flavours. Flavours of some ester are given below:

   Amylacetae  Banana 

Isobutyl acetate        Raspberry

Benzyl Acetate           Jasmine 

Ethyl Bytyrate            Pineapple 

    Amyl Butyrate           Apricot

    Actyl acetate             Orange 

Q6 What are peptides and peptide linkage 

Ans Peptides are the compounds formed by the condensation of two or more same different alpha amino acids. The condensation occur between the amino acids with elimination of water.

Q7 What is Ninhydrin test ? Give its application.

Ans It is the chemical analysis used to detect the presence of amino acids in the given mixyure. Ninhydrin reacts with amino acids to form the intense bluish violet colouration. Ninhydrin test is widely applied to visualize the amino acids seprated by paper chromatogrphy.

Q8 What is the Strecker's synthesis ?

Ans: When the Hydrogen cyanide is added to an Aldehyde in the presence of ammonia alpha amino nitirle is obtained which on hydrolysis in acid medium gives Alpha amino acids. This is called Strecker's synthesis.

What is the glacial acid ?

Ans the pure acetic acid freezes to ice likes solid 17 C degree. It is called glacial acid.

Q10 Define the amino acids. Give their Classification.

Ans Amino acid are the bifunctional organic compound containing the carboxyl group as well as Hdroxyl simultaneously. They are structural and functional units of proteins. Amino acids can be prepared by the general formula.

Classification of amino acid:

Acidic amino acids : The amino acids having one amino and two carboxyl groups e.g Aspartic acid

Basic amino acids : The amino acids having one carobxyl and two amino group e.g Lysine

Neutral amino acids : The amino acids having one carboxyl and one amino group e.g Alanine.

Essential amino acids : Those amino acid which cannot be prepared by body.

Non Essential amino acid : Those amino acid which can prepared by body .

amino acid may be alpha beta and gamma depending upon the position of amino group to which carbon they are attracted.