NEET Questions Solved


Acetamide and ethyl amine can be distinguished by reacting with             

(a) aq. HCl and heat

(b) aq. NaOH and heat

(c) acidified KMnO4

(d) bromine water

(b) When acetamide is heated with aq. NaOH it forms NH3 gas but ethylamine cannot form NH3.

 CH3CONH2 + H2ONaOHCH3COONa + NH3

CH3CH2NH2 + H2NaOHNo reaction

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Predict the product,                               

 

(a) Both aliphatic and aromatic secondary amines react with NaNO2 + HCl(HNO2) to form N-nitrosoamines which are insoluble in dilute mineral acids and separate out as neutral yellow oily compounds.

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Intermediates formed during the reaction of RCONH2 with Br2 and KOH are                                

(a) RCONHBr and RNCO

(b) RNHCOBr and RNCO

(c) RNHBr and RCONHBr

(d) RCONBr2

(a)  The reaction, RCONH2 + Br2 + KOH RNH2

 is known as Hofmann bromamide reaction. The mechanism of this is given as:

 

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The final product C, obtained in this reaction

Ac2OACH2COOHBr2BH+H2OC

would be

(a)                   (b) 

(c)                  (d) 

 

(a) Ac2OCH2COOHBr2H+H2O

                                                                                                

 

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Aniline is reacted with bromine water and the resulting product is treated with an aqueous solution of sodium nitrite in presence of dilute hydrochloric acid. The compound so formed is converted into a tetrafluoroborate which is subsequently heated. the final product is                                 

(a) 1,3,5-tribromobenzene

(b) p-bromofluorobenzene

(c) p-bromoaniline

(d) 2,4,6-tribromofluorobenzene

(d) -NH2 group is greatly activating group. Hence, a reaction takes place rapidly.

Difficulty Level:

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Aniline in a set of the following reactions yielded a coloured product Y.                        

 

(a) Key Idea NaNO2/HCl causes diazotisation of -NH2 group and the diazonium chloride gives a coupling product with active aryl nucleus.

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How many primary amines are posible for the formula C4H11N ?

(a) 1

(b) 2

(c) 3

(d) 4

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The product D in the following sequence of reactoins is, 

CH3COOH NH3 A Heat B P2O5 C Na + C2H5OH D :

(a) ester

(b) amine

(c) acid

(d) alcohol

(b) CH3COOHNH3CH3COONH4CH3CONH2P2O5CH3CNNa+C2H5OHCH3CH2NH2

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The IUPAC name of the compound having formula,

(a) 3-aminohydroxy propionic acid

(b) 2-amino-propan-3-oic acid

(c) amino hydroxy propionic acid

(d) 2-amino-3-hydroxy propionic acid

(d) Follow IUPAC rules.

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Which of the following is the strongest base ?

(a) Aliphatic amines are a stronger base than aromatic amines.

The basicity of amines is due to the nitrogen of the amine donating its lone pair of electrons. In aromatic amines, this lone pair is in conjugation(delocalized) with the aromatic ring. While in aliphatic mine this doesn't happen and thus the lone pair is ready to be donated.

 

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