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# NCERT solutions Chemistry Class 11 Part 2 chapter 12 Organic Chemistry - Some Basic Principles and Techniques

## Chapter 12 - Organic Chemistry - Some Basic Principles and Techniques

#### Pages 361 - 397

What are hybridisation states of each carbon atom in the following compounds?

CH2=C=O, CH3CH=CH2, (CH3)2CO, CH2=CHCN, C6H6

Q 1 | Page 361

Indicate the σ and π bonds in the following molecules:

C6H6

Q 2.1 | Page 361

Indicate the σ and π bonds in the following molecules:

C6H12

Q 2.2 | Page 361

Indicate the σ and π bonds in the following molecules:

CH2Cl2

Q 2.3 | Page 361

Indicate the σ and π bonds in the following molecules:

CH= C = CH2

Q 2.4 | Page 361

Indicate the σ and π bonds in the following molecules:

HCONHCH3

Q 2.5 | Page 361

Indicate the σ and π bonds in the following molecules:

CH3NO2

Q 2.5 | Page 361

Write bond line formulas for Isopropyl alcohol

Q 3.1 | Page 361

Write bond line formulas for 2,3-Dimethyl butanal

Q 3.2 | Page 361

Write bond line formulas for Heptan-4-one

Q 3.3 | Page 361

Give the IUPAC names of the following compound

Q 4.1 | Page 361

Write IUPAC names of the products obtained by the ozonolysis of the following compounds

Pent-2-ene

Q 4.1 | Page 396

Give the IUPAC names of the following compounds:

Q 4.2 | Page 361

Write IUPAC names of the products obtained by the ozonolysis of the following compounds:

3,4-Dimethyl-hept-3-ene

Q 4.2 | Page 396

Write IUPAC names of the products obtained by the ozonolysis of the following compounds:

2-Ethylbut-1-ene

Q 4.3 | Page 396

Give the IUPAC names of the following compounds:

Q 4.3 | Page 361

Give the IUPAC names of the following compounds:

Q 4.4 | Page 361

Give the IUPAC names of the following compounds:

Q 4.5 | Page 361

Give the IUPAC names of the following compounds:

Cl2CHCH2OH

Q 4.6 | Page 361

Which of the following represents the correct IUPAC name for the compounds concerned?

2,2-Dimethylpentane or 2-Dimethylpentane

Q 5.1 | Page 361

Which of the following represents the correct IUPAC name for the compounds concerned?

2,4,7-Trimethyloctane or 2,5,7-Trimethyloctane

Q 5.2 | Page 361

Which of the following represents the correct IUPAC name for the compounds concerned?

2-Chloro-4-methylpentane or 4-Chloro-2-methylpentane

Q 5.3 | Page 361

Which of the following represents the correct IUPAC name for the compounds concerned?

But-3-yn-1-ol or But-4-ol-1-yne

Q 5.4 | Page 361

Draw formulas for the first five members of each homologous series beginning with the given compounds

H–COOH

Q 6.1 | Page 362

Draw formulas for the first five members of each homologous series beginning with the given compounds

CH3COCH3

Q 6.2 | Page 362

Draw formulas for the first five members of each homologous series beginning with the given compounds.

H–CH=CH2

Q 6.3 | Page 362

Give condensed and bond line structural formulas and identify the functional group(s) present, if any, for :

2,2,4-Trimethylpentane

Q 7.1 | Page 362

Give condensed and bond line structural formulas and identify the functional group(s) present, if any, for

2-Hydroxy-1,2,3-propanetricarboxylic acid

Q 7.2 | Page 362

Give condensed and bond line structural formulas and identify the functional group(s) present, if any, for

Hexanedial

Q 7.3 | Page 362

Identify the functional groups in the following compound

Q 8.1 | Page 362

Identify the functional groups in the following compounds

Q 8.2 | Page 362

Identify the functional groups in the following compounds

Q 8.3 | Page 362

Which of the two: O2NCH2CH2O or CH3CH2O is expected to be more stable and why?

Q 9 | Page 362

Draw the cis and trans structures of hex-2-ene. Which isomer will have higher b.p. and why?

Q 9 | Page 397

Explain why alkyl groups act as electron donors when attached to a π system

Q 10 | Page 362

Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation.

C6H5OH

Q 11.1 | Page 362

Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation.

C6H5NO2

Q 11.2 | Page 362

Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation.

CH3CH = CH – CHO

Q 11.3 | Page 362

Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation.

C6H5CHO

Q 11.4 | Page 362

Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation.

Q 11.5 | Page 362

Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation

Q 11.6 | Page 362

What are electrophiles and nucleophiles? Explain with examples.

Q 12 | Page 362

Identify the reagents shown in bold in the following equations as nucleophiles or electrophiles:

a) CH3COOH +HO- → CH3COO− + H2O

b)

c)

Q 13 | Page 362

Classify the following reactions in one of the reaction type studied in this unit.

CH3CH2Br + HS → CH3CH2SH + Br

Q 14.1 | Page 362

Classify the following reactions in one of the reaction type studied in this unit.

(CH3)2 C = CH2 + HCl → (CH3)2 ClC–CH3

Q 14.2 | Page 362

Classify the following reactions in one of the reaction type studied in this unit.

CH3CH2Br + HO → CH2 = CH2 + H2O + Br

Q 14.3 | Page 362

Classify the following reactions in one of the reaction type studied in this unit.

(CH3)3 C – CH2 OH + HBr → (CH3)2 CBrCH2CH3 + H2O

Q 14.4 | Page 362

What effect does branching of an alkane chain has on its boiling point?

Q 15 | Page 397

What is the relationship between the members of following pairs of structures? Are they structural or geometrical isomers or resonance contributors?

a)

b)

c)

Q 15 | Page 362

For the following bond cleavages, use curved-arrows to show the electron flow and classify each as homolysis or heterolysis. Identify reactive intermediate produced as free radical, carbocation and carbanion.

Q 16.1 | Page 363

For the following bond cleavages, use curved-arrows to show the electron flow and classify each as homolysis or heterolysis. Identify reactive intermediate produced as free radical, carbocation and carbanion.

Q 16.2 | Page 363

For the following bond cleavages, use curved-arrows to show the electron flow and classify each as homolysis or heterolysis. Identify reactive intermediate produced as free radical, carbocation and carbanion.

Q 16.3 | Page 363

For the following bond cleavages, use curved-arrows to show the electron flow and classify each as homolysis or heterolysis. Identify reactive intermediate produced as free radical, carbocation and carbanion.

Q 16.4 | Page 363

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

Q 17 | Page 363

Give a brief description of the principles of the following techniques taking an example in each case.

Crystallisation

Q 18.1 | Page 363

Give a brief description of the principles of the following techniques taking an example in each case.

Distillation

Q 18.2 | Page 363

Give a brief description of the principles of the following techniques taking an example in each case.

Chromatography

Q 18.3 | Page 363

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

Q 19 | Page 363

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

Q 20 | Page 363

Discuss the chemistry of Lassaigne’s test.

Q 21 | Page 363

Differentiate between the principle of estimation of nitrogen in an organic compound by Dumas method

Q 22.1 | Page 363

Differentiate between the principle of estimation of nitrogen in an organic compound by Kjeldahl’s method.

Q 22.2 | Page 363

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

Q 23 | Page 363

Explain the principle of paper chromatography.

Q 24 | Page 363

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

Q 25 | Page 363

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

Q 26 | Page 363

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

Q 27 | Page 363

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

Q 28 | Page 363

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

Q 29 | Page 363

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

Q 30 | Page 364

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

Q 31 | Page 364

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.

Q 32 | Page 364

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.

Q 33 | Page 364

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.

Q 34 | Page 364

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 given compound.

Q 35 | Page 364

In the organic compound CH2=CH–CH2–CH2–C≡CH, the pair of hydridised orbitals involved in the formation of: C2 – C3 bond is:

(a) sp – sp2

(b) sp – sp3

(c) sp2 – sp3

(d) sp3– sp3

Q 36 | Page 364

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

Q 37 | Page 364

Which of the following carbocation is most stable?

a)

b)

c)

d)

Q 38 | Page 364

The best and latest technique for isolation, purification and separation of organic compounds is:

(a) Crystallisation

(b) Distillation

(c) Sublimation

(d) Chromatography

Q 39 | Page 364

The reaction: CH_3CH_2I + KOH_((aq)) -> CH_3CH_2OH + KI is classified as :

(a) electrophilic substitution

(b) nucleophilic substitution

(c) elimination