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.
No. DNA and RNA have nitrogen in the heterocyclic rings which cannot be removed as ammonia.
Kjeldahl method cannot be used to estimate nitrogen present in rings, azo and nitro groups as nitrogen present in these cannot be converted into ammonium sulphate.
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
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
Suggest a suitable technique for separating naphthalene from kerosene oil present in a mixture.
What are electrophiles? Explain electrophile substitution reaction with the help of example.
The IUPAC name for
(a) 1-Hydroxypentane-l, 4-dione
(b) 1,4-Dioxopentanol
(c) l-Carboxybutan-3-one
(d) 4-Oxopentanoic acid
Electronegativity of carbon atoms depends upon their state of hybridization. In which of the following compounds, the carbon marked with asterisk is most electronegative?
(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
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 .
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.
Name a suitable technique of separation of the components from a mixture of calcium sulphate and camphor.
Why is it necessary to use acetic acid and not sulphric acid for acidification of sodium extract for testing sulphur by lead acetate test?
Write the name of element which is confirmed on adding Na2[Fe(CN)5NO] in sodium extract solution due to appearance of violet colouration.
(a) What do you understand by Homolytic fission?
(b) What are carbanions? Give an example.
Covalent bonds can undergo fission in two different ways. The correct representation involving the heterolytic fission of CH3 – Br is
(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?
(a) 2-Ethyl-3-methylpentane
(b) 3,4-Dimethylhexane
(c) 2-sec-Butylbutane
(d) 2,3-Dimethylbutane
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.
Give a brief description of the principles of the following techniques taking an example in each case: (a) Crystallisation (b) Distillation (c) Chromatography
How will you separate a mixture of two organic compounds which have different solubilities in the same solvent?
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.
Covalent bonds can undergo fission in two different ways. The correct representation involving the heterolytic fission of CH3 – Br is
What are hybridisation states of each carbon atom in the following compounds? CH2=C=O, CH3CH=CH2, (CH3)2CO, CH2=CHCN, C6H6.
Indicate the a- and n-bonds in the following molecules:
C6H6 , C6H12, CH2Cl2, CH=C=CH2, CH3NO2, HCONHCH3
Describe the method, which can be used to separate two compounds with different solubilities in a solvent S.
(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)
Compounds with same molecular formula but differing in their structures are said to be structural isomers. What type of structural isomerism is shown by
Which of the following compounds will not exist as resonance hybrid? Give reason for your answer.
(a) CH3OH
(b) R-CONH2
(c) CH3CH = CHCH2NH2
Resonance structures of propenal are given below. Which of these resonating structures is more stable? Give reason for your answer.
Match Column I with Column II.
| Column I | Column II |
| (a) Dumas method | (1) AgN03 |
| (b) Kjeldahl method | (2) Silica gel |
| (c) Carius method | (3) Nitrogen gel |
| (d) Chromatography | (4) Free radicals |
| (e) Homolysis | (5) Ammonium sulphate |
Identify the reagents shown in bold in the following equations as nucleophiles or electrophiles
(a) CH3COOH + HO– ———–> CH3COO– + H2O
(b) CH3COCH3 + CN ———–> (CH3)2 C(CN)(OH)
(c) C6H5 + CH3CO ———–> C6H5COCH3
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
Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens ?
Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.
Explain, why an organic liquid vaporises at a temperature below its boiling point in its steam distillation ?
