Chemistry : Organic Chemistry – Some Basic Principles and Techniques

In Lassaigne's test for the detection of halogens, the sodium fusion extract is first boiled with concentrated nitric acid. This is

• to remove silver halides

• to decompose Na₂S and NaCN, if present

• to dissolve Ag₂S

• to dissolve AgCN, if formed

0.25 g of an organic compound on Kjeldahl's analysis gave enough ammonia to just neutralize 10 cm³ of 0.5 M H₂SO₄. The percentage of nitrogen in the compound is

• 28

• 56

• 14

• 112

Lassaigne's test for the detection of nitrogen fails in

• H₂N-CO-NHNH₂.HCl

• NH₂-NH₂.HCl

• NH₂-CO-NH₂

• C₆H₅-NH-NH₂.HCl

When tetrahydrafuran is treated with excess HI, the product formed is

• 1, 4-diiodobutane

• 1,4-butanediol

• 2-iodotetrahydrofuran

• 4-iodo-1-butanol

Pick out the correct statements from the following and choose the correct answer from the codes given below

1. Hexa-1, 5-diene is a conjugated diene
2. Prop-1, 2-diene is conjugated diene
3. Hexa-1, 3-diene is a conjugated diene
4. Buta-1, 3-diene is an isolated diene
5. Prop-1, 2-diene is a cumulative diene

• 1, 2

• 3, 5

• 2, 3

• 4, 5

Select R-isomers from the following

• I and III

• II, IV and V

• I, II and III

• II and III

The correct IUPAC name of the acid

• Z-3-ethyl-4methyl hex-3-en-1-oic acid

• E-3-ethyl-4-ethylhex-3-en-1-oic acid

• Z-3-ethyl-4-methyl hexanoic acid

• Z-3, 4-diethylpent-3-en-1-oic acid

(CH₃)₃CMgCl on reaction with D₂O produces

• (CH₃)₃COD

• (CD₃)₃CH

• (CH₃)₃CD

• (CD₃)₃CD

Which of the following process is suitable for the purification of aniline?

• Simple distillation

• Fractional distillation

• Fractional crystallisation

• Steam distillation

Of the isomeric hexanes, the isomers that give the minimum and maximum number of monochloro derivatives are respectively

• 3-methylpentane and 2,3-dimethylbutane

• 2,3-dimethylbutane and n-hexane

• 2,2-dimethylbutane and 2-methylpentane

• 2,3-dimethylbutane and 2-methylpentane