The most stable carbocation among the following is:

1. 2.
3. 4.

Subtopic:  Electron Displacement Effects |
 51%
From NCERT
NEET - 2018
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The correct statement about the SN1 reaction is:

1. 100 % racemisation.
2. Inversion more than retention leads to partial racemisation.
3. 100 % retention.
4. 100 % Inversion.

Subtopic:  Nucleophile & Electrophile |
 62%
From NCERT
NEET - 2015
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Which of the following statements is not correct for a nucleophile?
1. Nucleophile is a Lewis acid.
2. Ammonia is a nucleophile.
3. Nucleophiles attack low electron density sites.
4. Nucleophiles are not electron-seeking.

Subtopic:  Nucleophile & Electrophile |
 74%
From NCERT
NEET - 2015
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Two possible stereo-structures of CH3CHOH.COOH, that are optically active, called:

1. Diastereomers 2. Atropisomers
3. Enantiomers 4. Mesomers 
Subtopic:  Stereo Isomers |
 80%
From NCERT
NEET - 2015
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In Duma's method for estimation of nitrogen, 0.25 g of an organic compound gave 40 mL of nitrogen collected at 300 K temperature and 725 mm pressure. If the aqueous tension at 300 K is 25 mm, the percentage of nitrogen in the compound is:

1. 17.36 2. 18.20
3. 16.76 4. 15.76
Subtopic:  Purification of Organic Compounds |
 53%
From NCERT
NEET - 2015
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In which of the following compounds, the C—Cl bond ionization shall give the most stable carbonium ion?

1. 2.
3. 4.
Subtopic:  Reaction Intermediates ; Preparation & Properties |
 56%
From NCERT
NEET - 2015
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Hyperconjugation occurs among the following compounds:

  

1. I only 2. II only
3. III only 4. I and III
Subtopic:  Electron Displacement Effects |
 68%
From NCERT
NEET - 2015
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The enolic form of ethyl acetoacetate is given below-

 

The number of σ and π bonds in the enolic form are respectively:

1. 18 sigma bonds and 2 pi-bonds
2. 16 sigma bonds and 1 pi-bond
3. 9 sigma bonds and 2 pi-bonds
4. 9 sigma bonds and 1 pi-bond

Subtopic:  Hybridisation & Structure of Carbon Compounds |
 88%
From NCERT
NEET - 2015
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The total number of pi-bond electrons in the following structure are:
1. 4 2. 8
3. 12 4. 16
Subtopic:  Hybridisation & Structure of Carbon Compounds |
 66%
From NCERT
NEET - 2015
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In Kjeldahl’s method for estimation of nitrogen present in the soil sample, ammonia evolved from 0.75g of sample neutralized 10ml. of 1M H2SO4. The percentage of nitrogen in the soil is:

1. 37.33 2. 45.85
3. 25.75 4. 43.13
Subtopic:  Qualitative Analysis of Organic Compounds |
 72%
From NCERT
AIPMT - 2014
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