Chemistry

Organic Chemistry

Question:

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

Answer:

(b) Arrow denotes the direction of movement of electrons

ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-16
Since, Br is more electronegative than carbon, hence heterolytic fission occurs in such a way that CH3 gets the positive charge and Br gets the negative charge. Thus, option (b) is correct.

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Organic Chemistry

Q 1.

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 2.

What are electrophiles and nucleophiles? Explain with examples:

Q 3.

Which elements are estimated by Liebig’s Method?

Q 4.

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 5.

In Carius method, sulphur is estimated by precipitating it as which compound?

Q 6.

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

Q 7.

ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-8

(a) 2-Ethyl-3-methylpentane
(b) 3,4-Dimethylhexane
(c) 2-sec-Butylbutane
(d) 2,3-Dimethylbutane

Q 8.

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

Q 9.

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

Q 10.

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

Q 11.

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 12.

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

Q 13.

(a) Which is more suitable method for the purification of a compound in liquid state which decomposes at or below its boiling point?
(b) How will you separate a mixture of ammonium chloride and common salt?

Q 14.

Two or more compounds having same the molecular formula but different functional groups are called functional isomers. Which of die following pairs are not functional group isomers?
(a) II and III (b) II and IV
(c) I and IV (d) I and II

Q 15.

By mistake, an alcohol (boiling point 97 °C) was mixed with a hydrocarbon (boiling point 68 °C). Suggest a suitable method to separate the two compounds. Explain the reason for your choice.

Q 16.

Which gas is liberated in Kjeldhal’s method?

Q 17.

Which type of compounds are purified by steam distillation?

Q 18.

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

Q 19.

The IUPAC name for
ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-2

(a) 1-Hydroxypentane-l, 4-dione
(b) 1,4-Dioxopentanol
(c) l-Carboxybutan-3-one
(d) 4-Oxopentanoic acid

Q 20.

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 21.

Explain the terms inductive and electromeric effects. Which electron displacement effect explain the following correct orders of acidity of the carboxylic acids?
(a) Cl3CCOOH > Cl2CHCOOH > ClCH2 COOH
(b) CH3CH2COOH > (CH3)2 CHCOOH > (CH3)3CCOOH

Q 22.

Discuss the chemistry of Lassaigne’s test.

Q 23.

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

Q 24.

Name three types of chromatography.

Q 25.

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

Q 26.

Write the name of element which is confirmed on adding Na2[Fe(CN)5NO] in sodium extract solution due to appearance of violet colouration.

Q 27.

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 28.

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 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.

Which of the above compounds form pairs of metamers?

Q 31.

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

Q 32.

Give the TUPAC names of the following compounds:

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

Q 33.

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

Q 34.

What type of solids are separated by fractional crystallisation?

Q 35.

Write the structural formula of 4-chloro-2-pentene.

Q 36.

What is the basic principle of chromatography?

Q 37.

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

Q 38.

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 39.

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 40.

Identify the pairs of compounds which are functional group isomers.

Q 41.

Identify the pairs of compounds that represent chain isomerism.

Q 42.

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 43.

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 44.

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

Q 45.

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 46.

Suggest a suitable technique for separating naphthalene from kerosene oil present in a mixture.

Q 47.

What is Lassaigne’s extract?

Q 48.

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

Q 49.

Write all structural isomers of molecular formula C3H6O.

Q 50.

How will you detect the presence of nitrogen and sulphur in Lassaigne’s extract?