Chemistry

Organic Chemistry

Question:

Name the process used to separate sugar and salt.

Answer:

Fractional crystallisation using ethanol as a solvent.

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Organic Chemistry

Q 1.

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

Q 2.

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

Q 3.

Classify the following reactions in one of the reaction type studied in this unit.
(a) CH3CH2Br + HS ———–> CH3CH2SH + Br
(b) (CH3)2C=CH2 + HCl ———–> (CH3)2CCl—CH3
(c) CH3CH2Br + HO ———–> CH2=CH2 + H2O + Br
(d) (CH3)3C—CH2OH + HBr ———–> (CH3)2 C Br CH2CH2CH3 + H2O

Q 4.

In the Lassaigne’s test for ntrogen in an organic compound, the Prussian blue colour is obtaine d 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 5.

In which of the following compounds the carbon marked with asterisk is expected to have greatest positive charge?

ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-10

Q 6.

Which of the following represents the correct TUPAC 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- l-ol or But-4-ol-yne.

Q 8.

Which method is used to extract a compound in aqueous solution?

Q 10.

ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-4

(a) 1 -Chloro-2-nitro-4-methylbenzene
(b) l-Chloro-4-methyl-2-nitrobenzene
(c) 2-Chloro-1 -nitro-5-methylbenzene
(d) m-Nitro-p-chlorotoluene

Q 11.

Electrophilic addition reactions proceed in two steps. The first step involves the addition of an electrophile. Name the type of intermediate formed in the first step of the following addition reaction.
H3C-HC = CH2 + H+→ ?

(a) 2 °Carbanion                                                                        
(b) 1 ° Carbocation
(c) 2 ° Carbocation
(d) l °Carbanion

Q 12.

For testing halogens in an organic compound with AgN03 solution, sodium extract (Lassaigne's extract) is acidified with dilute HN03. What will happen if a student acidifies the extract with dilute H2S04 in place of dilute HN03?

Q 13.

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

Q 14.

What are electrophiles? Explain electrophile substitution reaction with the help of example.

Q 15.

What are hybridisation states of each carbon atom in the following compounds?  CH2=C=O, CH3CH=CH2, (CH3)2CO, CH2=CHCN, C6H6.

Q 16.

Arrange the following in increasing order of C—C bond length:  C2H & C2H4, C2H2.

Q 17.

(a) What do you understand by Homolytic fission?
(b) What are carbanions? Give an example.

Q 18.

0.15 g of an organic compound gave 0.12 g of Ag Br by the Carius method. Find percentage of Br in the compound.

Q 19.

Give the TUPAC names of the following compounds:

cbse-class-11th-chemistry-organic-chemistry-basic-principles-techniques-4

Q 20.

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

Q 21.

Name three types of chromatography.

Q 22.

Electronegativity of carbon atoms depends upon their state of hybridization. In which of the following compounds, the carbon marked with asterisk is most electronegative?
ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-6

 

Q 23.

Identify the pairs of compounds that represent position isomerism.

Q 24.

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

Q 25.

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

Q 26.

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

Q 27.

What is Lassaigne’s extract?

Q 28.

Write the hybridized state of C atoms in the following CH2 = CH – C-N

Q 29.

In which of the following representations given below spatial arrangement of group/atom is different from that given in structure ‘A'?

ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-21

Q 30.

What type of solids are separated by fractional crystallisation?

Q 31.

Complete the following:(CH3COO)2 Pb + Na2S ———->      

Q 32.

Give equation for the following:
(i) Electrophilic Substitution
(ii) Nucleophilic Substitution

Q 33.

Under what conditions can the process of steam distillation is used?

Q 34.

Covalent bonds can undergo fission in two different ways. The correct representation involving the heterolytic fission of CH3 – Br is

ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-15

Q 35.

The addition of HC1 to an alkene proceeds in two steps. The first step is the attack of H+ ion to >C = C< portion which can be shown as

ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-17

 

Q 36.

Hyperconjugation involves delocalization of .
(a) electrons of carbon-hydrogen σ bond of an alkyl group directly attached to an atom of unsatUrated system.
(b) electrons of carbon-hydrogen σ bond of alkyl group directly attached to the positively charged carbon atom.
(c) π-electrons of carbon-carbon bond.
(d) lone pair of electrons.

Q 37.

Which of the above compounds form pairs of metamers?

Q 38.

Identify the pairs of compounds which are functional group isomers.

Q 39.

Compounds with same molecular formula but differing in their structures are said to be structural isomers. What type of structural isomerism is shown by

ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-31

Q 40.

In DNA and RNA, nitrogen atom is present in the ring system. Can Kjeldahl method be used for the estimation of nitrogen present in these? Give reasons.

Q 41.

If a liquid compound decomposes at its boiling point, which method(s) will you choose for its purification? It is known that the compound is stable at low pressure, steam volatile and insoluble in water.

Q 42.

Draw formulas for the first five members of each homologous series beginning with the following compounds,
(a) H—COOH (b) CH3COCH3 (c) H—CH=CH2

Q 43.

What is the relationship between the members of following pairs of structures? Are they structural or geometrical isomers or resonance contributors?
cbse-class-11th-chemistry-organic-chemistry-basic-principles-techniques-10

Q 44.

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

Q 45.

Which of the following carbocation is most stable?
cbse-class-11th-chemistry-organic-chemistry-basic-principles-techniques-45

Q 46.

How will you separate a mixture of two organic compounds which have different solubilities in the same solvent?

Q 47.

Which gas is liberated in Kjeldhal’s method?

Q 48.

Name a suitable adsorbent used in the process of column chromatography.

Q 49.

Which type of compounds are purified by steam distillation?

Q 50.

How will you separate a mixture of Iodine and sodium chloride!