Introduction to Aromatic Compounds

Q. 58. The benzylic free radical is aromatic because it contains no. of p orbitals and no. of unpaired electrons .

Q. The number of benzylic hydrogen atoms in ethylbenzene is

1. 3
2. 5
3. 2
4. 7

Q. In paper chromatography,

1. Mobile phase is liquid and stationary phase is solid
2. Mobile phase is solid and stationary phase is liquid
3. Both phases are liquids
4. Both phases are solids

Q.

Explain the principle of crystallization.

Q. Which of the following is not an example of adsorption chromatography?

1. Paper chromatography
2. Thin layer chromatography
3. Column chromatography
4. All of the above

Q. 26.Among the following, the molecule of high dipole moment is (1) CCl4. (2)NH3. (3) H2O. (4)CHCl3

Q. 5. Why dipole moment in 1, 4-dichlorohexane is not zero ?

Q. The principle of paper chromatography is :

1. Column chromatography
2. Partition chromatography
3. TLC
4. None of the above

Q. Which of the following statements is not applicable to Lassaigne's test?

1. The extra elements (N, S and halogens) are tested as their inorganic salts.
2. During fusion of the organic compound iwth sodium, $N{a}_{2}S,NaCN$ and $NaX$ are formed.
3. It can even be used for the detection of hydrogen in the organic compound.
4. It is possible to differentiate between the different halogens.

Q. Chromatography is based on the :

1. Different rate of movement of the solvent in the column
2. Different rate of movement of components in the mixture
3. Separation of one solute from other constituents by being captured on the adsorbent
4. None of the above

Q. Arenes generally undergoes :

1. Electrophilic addition reaction
2. Electrophilic substitution reaction
3. Nucleophilic substitution reaction
4. All of the above.

Q. Which compound is generally used as a mobile phase in paper chromatography?

1. Acetone
2. Alcohol
3. Benzene
4. None of these

Q. Which of the following will show aromatic behaviour

1. 
2. 
3. 
4. 

Q. When a mixture of sugar and common salt has to be separated using simple crystallisation we use ethanol as a suitable solvent; at 75°C sugar is soluble in suitable solvent and NaCl is not, so its sugar which crystallises out. Then why does the less soluble substance crystallise out first in fractional crystallisation ?

Q. Which of the following can be used as adsorbent in adsorption chromatography?

1. Silica
2. Alumina
3. Both a and b
4. None of the above

Q.

Magnesium liberates $H_2$ on reaction with

1. dil.HCl

2. All of these

3. very dil.
   

4. dil

Q.

Define crystallization.

Q. Q 24/90 All of the given compounds have zero dipole moment except BF3, BeF2, co2, nh,

Q. The number of sigma and pi bonds present in inorganic benzene are respectively

Q.

1. I < II < III

2. III = II < I

3. II < III < I

4. I < III < II

Q. 19. Why is benzoquinone not aromatic?

Q.

What is the basis of fractional crystallization?

Q. What r planar compounds, Y do they show non aromatic

Q. Why bond enthalpy of Carbon monoxide bond is more than that of N_2?

Q. In lead acetate test of sulfur detection, Lassaigne extract is acidified with ______ and then lead acetate solution is added.

1. Oxalic acid
2. Hydrochloric acid
3. Sulphuric acid
4. Acetic acid

Q. Why alkynes do not show geometric isomerism as it also have π bond so it should also show restricted rotation and hence geometric isomerism.

Q.

Which of the following are functional isomers of?

1. 

2. 

3. Neither (a) nor (b)

4. Both (a) & (b)

Q. The fusion of an organic compound with solid sodium metal is undertaken for testing nitrogen, sulphur and halogens. This test is called:

1. Dumas method
2. Carius method
3. Kjeldahl's method
4. Lassaigne's test

Q.

Which of the following is the laboratory method to prepare benzene?

Q. benzene + hno3 gives A -----zndust/ aq naoh--->