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?
On adding dilute H2S04 for testing halogens in an organic compound with AgN03, white precipitate of Ag2S04 is formed. This will interfere with the test of chlorine and this Ag2S04 may be mistaken for white precipitate of chlorine as AgCl. Hence, dilute HN03 should be used instead of dilute H2S04.
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?
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
In which of the following compounds the carbon marked with asterisk is expected to have greatest positive charge?
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 .
Which of the following represents the correct TUPAC name for the compounds concerned?
(a) 2, 2-Dimethylpentane or 2-Dimethylpentane (b) 2, 4, 7-Trimethyloctane or 2, 5, 7- Trimethyloctane (c) 2-Chloro-4-methylpentane or 4-Chloro-2-methylpentane (d) But-3-yn- l-ol or But-4-ol-yne.
(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
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
What are electrophiles? Explain electrophile substitution reaction with the help of example.
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?
What are hybridisation states of each carbon atom in the following compounds? CH2=C=O, CH3CH=CH2, (CH3)2CO, CH2=CHCN, C6H6.
(a) What do you understand by Homolytic fission?
(b) What are carbanions? Give an example.
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.
Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen, sulphur and halogens.
Electronegativity of carbon atoms depends upon their state of hybridization. In which of the following compounds, the carbon marked with asterisk is most electronegative?
Discuss the principle of estimation of halogens, sulphur and phosphorus present in an organic compound.
Will CCl4 give white precipitate of AgCl on heating it with silver nitrate? Give reason for your answer.
In which of the following representations given below spatial arrangement of group/atom is different from that given in structure ‘A'?
Give equation for the following:
(i) Electrophilic Substitution
(ii) Nucleophilic Substitution
Which of the following^ the correct IUPAC name?
(a) 3-Ethyl-4,4-dimethylheptane
(b) 4,4-Dimethyl-3-ethylheptane
(c) 5-Ethyl-4,4-dimethylheptane
(d) 4,4-Bis(methyl)-3-ethylheptane
Covalent bonds can undergo fission in two different ways. The correct representation involving the heterolytic fission of CH3 – Br is
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
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.
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.
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.
Write structural formulae for compounds named as
(a) 1-Bromoheptane
(b) 5-Bromoheptanoic acid
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.
Match the terms mentioned in Column I with the terms in Column II.
| Column I | Column II |
| (a) Carbocation | (1) Cyclohexane and 1-hexene |
| (b) Nucleophile | (2) Conjugation of electrons of C – H σbond with empty p-orbital present at adjacent positively charged carbon. |
| (c) Hyperconjugation | (3) sp2 hybridised carbon with empty p-orbital |
| (d) Isomers | (4) Ethyne |
| (e) sp hybridization | (5) Species that can receive a pair of electrons |
| (f) Electrophile | (6) Species that can supply a pair of electrons |
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 |
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
What is the relationship between the members of following pairs of structures? Are they structural or geometrical isomers or resonance contributors?
0.3780 g of an organic compound gave 0.5740 g of silver chloride in Carius estimation. Calculate the percentage of chlorine in the compound.
