ORGANIC CHEMISTRY - SOME BASIC PRINCIPLES AND TECHNIQUES Quiz-19

Organic chemistry - some basic principles and techniques Quiz-19

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IIT JEE exam which consists of JEE Main and JEE Advanced is one of the most important entrance exams for engineering aspirants. The exam is held for candidates who are aspiring to pursue a career in the field of engineering and technical studies. Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything..

Q1.The number of σ- and π-bonds in 1-buten-3-yne is:

•  5 σ and 5 π
•  7 σ and 3 π
•  8 σ and 2 π
•  6 σ and 4 π

Solution

Q2.The most strained cycloalkane is:

•  Cyclopropane
•  Cyclobutane
•  Cyclopentane
•  Cyclohexane

Solution

Q3. Consider the following reaction:

•  
•  
•  
•  

Solution
Br is less reactive and more selective. Thus the formation of 3° radical will be the major product

Q4. In which of the following compounds, nitrogen cannot be tested by Lassaigne's test?

•  CH_3 CONH_2
•  NH_2⋅NH_2⋅H_2 O
•  C_6 H_5 NH_2
•  C_6 H_5 NO_2

Solution
Positive Lassiagne's test is given by containing both C and N a. NH_2 CONH_2 (Contains both C and N) b.NH_2-NH_2 (Does not contain C). So, the test is not given by (b) c. Glycine (NH_2-CH_2-COOH).(Contains both C and N) d.Ph–NH— NH_2 (Contains both C and N)

Q5. In the estimation of nitrogen by Kjeldahl's method,2.8 gm of an organic compound required 20 millimole ofH_2 SO_4 for the complete neutralisation of NH_3gas evolved. The percentage of nitrogen in the sample is:

•  20%
•  10%
•  40%
•  30%

Solution
 

Q6. Hydride shift from C-2 will give the most stable resonance stabilized carbocation as

•  CH_3 at C-4
•  H at C – 4
• CH_3 at C-2
•  H at C-2

Solution
In the following carbocation; H/CH_3 that is most likely to migrate to the positively charged carbon is

Q7. Among the following, the compound that can be most readily sulphonated is:

•  Benzene
•  Nitrobenzene
•  Toluene
•  Chlorobenzene

Solution
SE reactions are favoured by EDG. CH_3ise ̅-donating by +I effect, whereas (-Cl) is EW by –I effect, and (–NO_2) is EW by –I and –R . So toluene undergoes SE reaction most readily

Q8. The IUPAC name of vinyl acetylene is:

•  Pent-1-en-4-yne
•  Pent-4-yn-1-ene
•  But-1-en-3-yne
•  But-1-yn-3-ene

Solution

Q9. C_2 is rotated anticlockwise 102°C about C_2-C_3 bond. The resulting conformer is

•  Partially eclipsed
•  Eclipsed
•  gauche
•  Staggered

Solution

Q10. A Compound containing 80%C and 20%H is likely to be:

•  C_3 H_8
•  CH_4
•  C_6 H_6
• C_2 H_6

Solution