Chemistry

Organic Chemistry

Question:

Which of the above compounds form pairs of metamers?

Answer:

V and VI, VI and VII and V and VII form pairs of metamers because they have different alkyl chains on either side of ethereal oxygen (-O-).

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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.

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

Q 3.

What are electrophiles and nucleophiles? Explain with examples:

Q 4.

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

Q 5.

Which type of compounds are purified by steam distillation?

Q 6.

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 7.

Which gas is liberated in Kjeldhal’s method?

Q 8.

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

Q 9.

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 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.

Give the TUPAC names of the following compounds:

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

Q 12.

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

Q 13.

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

Q 14.

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

Q 15.

Name three types of chromatography.

Q 16.

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

Q 17.

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 18.

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 19.

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 20.

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 21.

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 22.

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

Q 23.

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

Q 24.

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 25.

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 26.

cbse-class-11th-chemistry-organic-chemistry-basic-principles-techniques-35

Q 27.

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 28.

Identify the pairs of compounds which are functional group isomers.

Q 29.

Identify the most stable species in the following set of ions giving reasons:
ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-42
 

Q 30.

Which of the following compounds will not exist as resonance hybrid? Give reason for your answer.

(a) CH3OH
(b) R-CONH2
(c) CH3CH = CHCH2NH2

Q 31.

Discuss the chemistry of Lassaigne’s test.

Q 32.

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

Q 33.

What type of solids are separated by fractional crystallisation?

Q 34.

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 35.

What is the basic principle of chromatography?

Q 36.

(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 37.

Explain hyperconjugation effect. How does hyperconjugation effect explain the stability ofalkenes ?

Q 38.

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 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.

Resonance structures of propenal are given below. Which of these resonating structures is more stable? Give reason for your answer.
ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-46
 

Q 41.

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

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.

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

Q 44.

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 45.

Which of the following compounds contain all the carbon atoms in the same hybridization state?
ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-19
 

Q 46.

Nucleophile is a species that should have
(a) a pair of electrons to donate
(b) positive charge
(c) negative charge
(d) electron deficient species

Q 47.

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 48.

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 49.

Write the structures of various carbocations that can be obtained from 2-methylbutane. Arrange these carbocations. in order of increasing stability.

Q 50.

Indicate the a- and n-bonds in the following molecules:
C6H6 , C6H12, CH2Cl2, CH=C=CH2, CH3NO2, HCONHCH3