Chemistry

Organic Chemistry

Question:

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.

Answer:

cbse-class-11th-chemistry-organic-chemistry-basic-principles-techniques-34

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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.

Which elements are estimated by Liebig’s Method?

Q 3.

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

Q 4.

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 5.

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 6.

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 7.

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

Q 8.

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

Q 9.

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 10.

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

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.

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 13.

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

Q 14.

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 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.

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

Q 17.

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 18.

Which gas is liberated in Kjeldhal’s method?

Q 19.

Which type of compounds are purified by steam distillation?

Q 20.

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 21.

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

Q 22.

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 23.

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

Q 24.

Give a brief description of the principles of the following techniques taking an example in each  case: (a) Crystallisation (b) Distillation (c) Chromatography

Q 25.

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

Q 26.

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

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.

(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 29.

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 30.

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

Q 31.

What are electrophiles and nucleophiles? Explain with examples:

Q 32.

Discuss the chemistry of Lassaigne’s test.

Q 33.

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

Q 34.

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

Q 35.

Name three types of chromatography.

Q 36.

What is the basic principle of chromatography?

Q 37.

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 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.

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

Q 40.

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

Q 41.

cbse-class-11th-chemistry-organic-chemistry-basic-principles-techniques-26

Q 42.

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

Q 43.

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

Q 44.

(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 45.

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 46.

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 47.

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 48.

Which of the above compounds form pairs of metamers?

Q 49.

Identify the pairs of compounds which are functional group isomers.

Q 50.

Explain how is the electronegativity of carbon atoms related to their state of hybridization in an organic compound?