Chemistry

Organic Chemistry

Question:

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

Answer:

(a, c) (a) II and III have the same functional group.
(c) I and IV have the same functional group.

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Organic Chemistry

Q 1.

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 2.

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

Q 3.

Why is an organic compound fused with Sodium for testing nitrogen, halogens and sulphur?

Q 4.

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 5.

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

Q 7.

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 8.

0 .12 g of an organic compound containing phosphorous gave 0.22 g of Mg2 P2O7 by usual analysis. Calculate the percentage of phosphorous in the compound.

Q 10.

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

Q 11.

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

Q 12.

Explain why (CH3)3C+ is more stable than CH3C+H2.

Q 13.

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 14.

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 15.

What type of solids are separated by fractional crystallisation?

Q 16.

(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 17.

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 18.

Draw the resonance structures of the following compounds:
ncert-exemplar-problems-class-11-chemistry-chapter-12-organic-chemistry-some-basic-principles-40
 

Q 19.

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

Q 20.

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

Q 21.

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

Q 22.

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 23.

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 24.

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

Q 25.

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 26.

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

Q 27.

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

Q 28.

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 29.

What is the hybridization of each carbon in H7C = C = CH7?

Q 30.

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 31.

In an estimation of sulphur by Carius method, 0.468 of an organic sulphur compound gave 0.668 g of barium sulphate. Find the percentage of sulphur in the compound.

Q 32.

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

Q 33.

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

Q 34.

Match the type of mixture of compounds in Column I with the technique of separation/purification given in column II.

Column I Column II
(a) Two solids which have different solubilities in a solvent and which do not undergo reaction when dissolved in it. (1) Steam distillation
(b) Liquid that decomposes at its boiling point (2) Fractional distillation
(c) Steam volatile liquid (3) Simple distillation
(d) Two liquids which have boiling points close to each other (4) Distillation under reduced pressure
(e) Two liquids with large difference in boiling points. (5) Crystallisation

Q 35.

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

Q 36.

Which elements are estimated by Liebig’s Method?

Q 37.

Why is an organic compound fused with sodium in Lassaigne’s test?

Q 38.

(a) What is the basic principle involved in the estimation of nitrogen by Dumas method.
(b) In a Dumas nitrogen estimation method, 0.30 g of an organic compound gave 50 cm3 of N2 collected at 300 K and 715 mm Hg pressure. Calculate the percentage composition of nitrogen in the compound. (Vapour pressure of water at 300 K is 15 mm Hg)

Q 39.

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 40.

Identify the pairs of compounds that represent position isomerism.

Q 41.

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

Q 42.

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

Q 43.

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

Q 44.

What is the basic principle of chromatography?

Q 45.

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 46.

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 47.

Explain the principle of paper chromatography.

Q 48.

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

Q 49.

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 50.

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