Free NCERT Solutions For Class 11 Chemistry Chapter 12 : Organic Chemistry – Some Basic Principles & Techniques Free PDF Download

Question 3:
Write bond line formulas for: Isopropyl alcohol, 2,3-Dimethyl butanal, Heptan-4-one.

Question 5:
Which of the following represents the correct IUPAC name for the compounds concerned? (a) 2,2-Dimethylpentane or 2-Dimethylpentane (b) 2,4,7-Trimethyloctane or 2,5,7- Trimethyloctane (c) 2-Chloro-4-methylpentane or 4-Chloro-2-methylpentane (d) But-3-yn-1-ol

Question 7:
Give condensed and bond line structural formulas and identify the functional group(s) present, if any, for :
(a) 2,2,4-Trimethylpentane
(b) 2-Hydroxy-1,2,3-propanetricarboxylic acid
(c) Hexanedial

Question 8:
Identify the functional groups in the following compounds
(a)

Question 12:
What are electrophiles and nucleophiles? Explain with examples.

Question 16:
For the following bond cleavages, use curved-arrows to show the electron flow andclassify each as homolysis or heterolysis. Identify reactive intermediate produced as freeradical, carbocation and carbanion.

Question 17:
Explain the terms Inductive and Electromeric effects. Which electron displacement effect explains the following correct orders of acidity of the carboxylic acids?
(a) Cl3CCOOH > Cl2CHCOOH > ClCH2COOH
(b) CH3CH2COOH > (CH3)2CHCOOH > (CH3)3C.COOH

Question 18:
Give a brief description of the principles of the following techniques taking an example in each case.
(a) Crystallisation
(b) Distillation
(c) Chromatography

Question 19:
Describe the method, which can be used to separate two compounds with different solubilities in a solvent S.

Question 20:
What is the difference between distillation, distillation under reduced pressure and steam
distillation?

Question 21:
Discuss the chemistry of Lassaigne’s test.

Question 22:
Differentiate between the principle of estimation of nitrogen in an organic compound by
(i) Dumas method and
(ii) Kjeldahl’s method.

Question 23:
Discuss the principle of estimation of halogens, sulphur and phosphorus present in an organic compound.

Question 24:
Explain the principle of paper chromatography.

Question 25:
Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens?

Question 26:
Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.

Question 27:
Name a suitable technique of separation of the components from a mixture of calcium sulphate
and camphor.

Question 28:
Explain, why an organic liquid vaporises at a temperature below its boiling point in its steam
distillation?

Question 29:
Will CCl4 give white precipitate of AgCl on heating it with silver nitrate? Give reason for your
answer.

Question 30:
Why is a solution of potassium hydroxide used to absorb carbon dioxide evolved during the
estimation of carbon present in an organic compound?

Question 31:
Why is it necessary to use acetic acid and not sulphuric acid for acidification of sodium extract
for testing sulphur by lead acetate test?

Question 32:
An organic compound contains 69% carbon and 4.8% hydrogen, the remainder being oxygen.
Calculate the masses of carbon dioxide and water produced when 0.20 g of this substance is subjected to complete combustion.

Question 33:
A sample of 0.50 g of an organic compound was treated according to Kjeldahl’s method. The ammonia evolved was absorbed in 50 mL of 0.5 M H2SO4. The residual acid required 60 mL of 0.5 M solution of NaOH for neutralisation. Find the percentage composition of nitrogen in the compound.

Question 34:
0.3780 g of an organic chloro compound gave 0.5740 g of silver chloride in Carius estimation. Calculate the percentage of chlorine present in the compound.

Question 35:
In the estimation of sulphur by Carius method, 0.468 g of an organic sulphur compound afforded 0.668 g of barium sulphate. Find out the percentage of sulphur in the givencompound.

Question 37:
In the Lassaigne’s test for nitrogen in an organic compound, the Prussian blue colour is obtained due to the formation of:
(a) Na4[Fe(CN)6]
(b) Fe4[Fe(CN)6]3
(c) Fe2[Fe(CN)6]
(d) Fe3[Fe(CN)6]4

Question 39:
The best and latest technique for isolation, purification and separation of organic compounds is:
(a) Crystallisation
(b) Distillation
(c) Sublimation
(d) Chromatography