A Level Chemistry 9701 (Chap 27,28)(Nitrogen Compounds,Polymers)

Which one is the weakest base?

• Ethylamine

• Methylamine

• Ammonia

• Phenylamine

Answer explanation

Phenylamine

A student wants to prepare ethylamine (a primary amine) with the help of the given reaction but he risks forming secondary and tertiary amines. Choose the right set of conditions for him to work.

• Excess conc. ammonia solution

• Excess conc. ethanolic ammonia

• Excess conc. ethanolic ammonia with heat

• Excess conc. ethanolic ammonia with heat and pressure

Answer explanation

Excess conc. ethanolic ammonia with heat and pressure

A student wants to prepare the compound shown; diethylamine (a secondary amine). Choose the right set of reactants and conditions for him to work.

• Ethylamine reacting with ethyl bromide under heat

• Ethylamine reacting with ethyl bromide under heat and pressure

• Excess conc. ethanolic ammonia with heat reacting with ethyl bromide

• Excess conc. ethanolic ammonia with heat and pressure reacting with ethyl bromide

Answer explanation

Ethylamine reacting with ethyl bromide under heat and pressure (sealed tube)

A student wants to make ethylamine with a 2 step process. Choose the correct step 1 and step 2 for a successful process. (This question requires you to choose 2 correct options out of 4)

• Step 1: Convert halogenoalkane to Alkane nitrile

• Step 1: Convert aldehyde to Alkane nitrile

• Step 2: Convert Alkane nitrile to Ehtylamine by the process of reduction

• Step 2: Convert Alkane nitrile to Ethylamine by the process of alkaline hydrolysis

Answer explanation

Step 1: Convert halogenoalkane to Alkane nitrile

Step 2: Convert Alkane nitrile to Ehtylamine by the process of reduction

How can you convert amides to primary amines?

• Reduction with LiAlH₄ in dry ether

• Reduction with NaBH₄ in aqueous conditions

• Acidic Hydrolysis

• Alkaline Hydrolysis

Answer explanation

Reduction with LiAlH₄ in dry ether

A student wanted to prepare phenylamine with the given process. He carried out a reduction reaction by heating nitrobenzene under the reflux with Tin (Sn) and concentrated hydrochloric acid. Instead of getting phenylamine, the resulting acidic mixture gave him the ion C₆H₅N⁺H₃ and he did not know what to do next. Choose the right step for him.

• Add HCl and then steam distill

• Just steam distill

• Just add NaOH

• Add NaOH and then steam distill

Answer explanation

Add NaOH and then steam distill

What is the color of the precipitate in the given example?

• Red-brown ppt

• Blue-black ppt

• White ppt

• First yellow then brown after 10-15 minutes

Answer explanation

White ppt

Properly name the steps 1 and 2. (This questions requires you to choose 2 correct options out of 4)

• Step 1: Diazotisation

• Step 1: Aromatisation

• Step 2: Coupling Reaction

• Step 2: Diaozotisation

Answer explanation

Step 1: Diazotisation

Step 2: Coupling Reaction

The reaction mixture is supposed to be kept below 10^ₒC because:

• Nitrous Acid does not react at higher temperatures

• The diazonium ion is converted to a diazonium salt

• The diazonium ion reacts with the negative nitrate (III) ions in the reaction mixture to form another product

• The diazonium ion is unstable and decomposes easily to give off nitrogen gas

Answer explanation

The diazonium ion is unstable and decomposes easily to give off nitrogen gas

What is the correct general structural formula of an amino acid (2-aminocarboxylic acid)?

• RCH(NH₂)COOH

• RCH₂(NH)COOH

• R¹R²C(NH₂)COOH

• R₃C(NH₂)COOH

Answer explanation

RCH(NH₂)COOH