NEETprep Bank NEET Chemistry Differentiations & Conversions - Organic Chemistry Questions Solved


A compound A of formula C3H6Cl2 on reaction with alkali can give B of formula C3H6O or C of formula C3H4. B on oxidation gave a compound of the formula C3H6O. C with dilute H2SO4 containing Hg2+ ion gave D of formula C3H6O, which with bromine and NaOH gave the sodium salt of C2H4O2. Then A is :

(a) CH3CH2CHCl2

(b) CH3CCl2CH3

(c) CH2ClCH2CH2Cl

(d) CH3CHClCH2Cl

 

(a) 

 

 or CH3CCH H+,Hg2+H2O CH3COCH+NaOHBr2 CHBr3 +CH3COONa
Since, B and D are different thus. B is CH3CH2CHO and so A is CH3CH2CHCl2.

Difficulty Level:

  • 41%
  • 36%
  • 17%
  • 8%

Identify the product (A) in following reaction series, CH3CNNa/C2H5OH(X)HNO2(Y)O(Z)Tollens reagent(A) :

(a) CH3CHO

(b) CH3CONH2

(c) CH3COOH

(d) CH- CH2-NHOH

(c) CH3CNNa/C2H5OHCH3CH2NH2HNO2CH3CH2OHOCH3CHOTollens reagentCH3COOH

Difficulty Level:

  • 23%
  • 21%
  • 46%
  • 12%

Vapour density of an organic compound is 23.0. It contains 52.17% of carbon and 13% of hydrogen. The compound gives iodoform test. The compound is:

(a) ethanol                               

(b) dimethyl ether

(c) acetone                             

(d) methanal

(a) Molar mass of compound  is 46 which is of ethanol. It also gives iodoform test.                               

Difficulty Level:

  • 42%
  • 20%
  • 31%
  • 9%

Compound (A), C8H9Br , gives a white precipitate when warmed with alcholic AgNO3. Oxidation of (A) gives an acid (B), C8H6O4. (B) easily forms anhydride on heating. Identify the compound (A).

(a)

 

(b)

 

(c)

 

(d)

 

(b) 

Difficulty Level:

  • 29%
  • 42%
  • 16%
  • 15%

Which of the following will give yellow precipitate with I2/NaOH?

1. CH3-CO-O-CO-CH3

4.Both (2) and (3)

(4) fact

Difficulty Level:

  • 13%
  • 13%
  • 31%
  • 45%

A nitrogeneous substance X is treated with HNO2 and the product so formed is further treated with NaOH solution, which produces blue colouration. X can be

1. CH3CH2NH2       R   R'  R"  C  OH  Red P+I2     I      AgNO2     NO2

2 CH3CH2NO2

3. CH3CH2ONO

4 (CH3)2CHNO2

(4) In Victor Meyer Test, secondary nitro compounds give blue colour.

R-CH2OH  Red P+I2 R-CH2-I  AgNO2  R-CH2-NO2
                                              

 

Difficulty Level:

  • 39%
  • 25%
  • 17%
  • 20%

The compound which reacts fastest with Lucas reagent at room temperature is:
1. Butan-1-ol
2. Butan-2-ol
3. 2-methylpropan-1-ol
4. 2-methylpropan-2-ol

(4) The order of reactivity of alcohol towards Lucas reagent is: 3°> 2°> 1°

Difficulty Level:

  • 12%
  • 16%
  • 11%
  • 63%

Methanol and ethanol can be distinguished by the following:
1. By reaction with metallic sodium
2. By reaction with caustic soda
3. By heating with iodine and washing soda
4. By heating with zinc and inorganic mineral acid

(3) Ethanol can give iodoform reaction while methanol can't give.

Difficulty Level:

  • 11%
  • 15%
  • 61%
  • 14%

Identify (X) in the sequence :

C3H8O H2SO4K2Cr2O7 C3H6O WarmI2 +NaOH CHI3

(1) CH3-CH2-CH2OH

(2) 

(3) CH3-O-CH2-CH3

(4) CH3-CH2-CHO


(2)

Difficulty Level:

  • 15%
  • 63%
  • 14%
  • 11%

In order to accomplish the following conversion, what reagent and conditions would be required?

1. Cold sodium hydroxide

2. Hot conc. sodium hydroxide

3. Potassium tertiary butoxide and heat

4. Hot water

(3)

Difficulty Level:

  • 12%
  • 42%
  • 42%
  • 6%