1.In this reaction amide is treated with bromine in presence of sodium hydroxide to prepare primary amine.
2.This method is used to prepare only primary amine not secondary and tertiary amine.
3.In this reaction product has one carbon less than reactant that’s why it is called degradation reaction.
Answers are given in the end-
1.Amines are basic in nature . Why?
2.Arrange the following amines in decreasing order of their basic strength. Give reason also.
(CH3)3N > (CH3)2NH > CH3NH2 > NH3 In aqueous phase
3. Arrange the following amines in decreasing order of their basic strength. Give reason also.
C2H5NH2 > (C2H5)2NH > (C2H5)3N > NH3 In aqueous phase
4. Arrange the following amines in decreasing order of their basic strength. Give reason also.
(CH3)2NH > (CH3)3N > CH3NH2 > NH3 in gaseous phase
5.Arrange the following amines in decreasing order of their basic strength. Give reason also.
6. Methanamine is less basic than aniline. Why?
7.Anilene does not gives friedal craft,s reaction.Why?
8.Why does amine group is protected by acetylating it?
9. Explain briefly
(a) Carbylamine reaction( Isocyanide test)
10. pKb value of ethylamine is lower than benzylamine
Answer
1.Basic nature of amine is attributed to presence of lone pair of electron on nitrogen atom of amine group which can be donated.
2. (CH3)2NH > CH3NH2 > (CH3)3N > NH3 (This order is combine effect of three factors.In aqueous phase, inductive effect, solvation effect and steric hindrance also play important roles)
3.(C2H5)2NH > (C2H5)3N > C2H5NH2 > NH3 (This order is combine effect of three factors.In aqueous phase, inductive effect, solvation effect and steric hindrance also play important roles)
4. (CH3)3N > (CH3)2NH > CH3NH2 > NH3 ( Due to Steric hinderance increases from primary to tertiary amine which hinder to donate lone pair of electron.)
5.
Methyl group, having +I effect increases the electron density on Nitrogen of amine whereas electron withdrawing(-I and –M effect) nitro group decreases electron density on nitrogen of benzene ring.
6.Due to +I effect of methyl group electron density increases in N of amine group whereas electron density decreases due to involvement of lone pair of electrons in resonance.
7. Because basic group amine (-NH2) reacts with friedal craft,s reagents which is acidic in nature and nitrogen bears +ive charge. This +vely charged nitrogen deactivate to the benzene ring due to its elecrtron withdrawing effect.
8. Amine group is protected by acetylating ( addition of -COCH3) it therefore it does not react with friedal craft,s reagens and able to perform friedal craft reaction.
9.When primary amine is treated with chloroform (CHCl3) in presence of base (KOH) yields isocyanide having offensive smell.
R-NH2 + CHCl3 +3 KOH –> R-NC + 3KCl + H2O
10.( pKb value lower mean basic strength is higher) Due to +I effect of ethyl group electron density increases in N of amine group, therefore ethamine is more basic whereas aniline is less basic as electron density decreases due to involvement of lone pair of electrons in resonance.
Answers are given in the end-
1. How will you distinguish butanol, butan-2-ol and 2-Methylbutan-2-ol
2. How will you distinguish aniline and phenol?
3.How will you distinguish phenol and ethanol?
4.How will you distinguish ethanamine and N-Methyl methanine.
5.How will you distinguish Propanamine and N,N-Dimethylethanamine.
6.How will you distinguish Propanamine, N-Methyethanamine and N,N-Dimethylmethanamine.
7. How will you distinguish Ethanol and Ethanoic acid.
8.How will you distinguish Methanal and Ethanal?
9.How will you distinguish Propanal and Propanol.
10.How will you distinguish Propanol and Ethanol?
11.How will you distinguish Choloromethane and Chlorobenzene.
Answer-
1.When Licas reagent (ZnCl2 + HCl ) is added than turbidity appears immediately in Methylbutan-2-ol ( tertiary alcohol), turbidity appears after 5 minutes in butan-2-ol ( Secondary alcohol) and no turbidity appears in butanol ( Primary alcohol).
2.Phenol gives violet colour with neutral FeCl3 while aniline does not.
3.Ethanol gives red colour with ceric ammonium nitrate while phenol does not.
4.Ethanamine reacts with benzenesulphonyl chloride( Hinesburg’s Reagent) which is soluble in dilute solution of NaOH, whereas N-Methyl methanine reacts but insoluble in dilute solution of NaOH.
5.Propanamine reacts with benzenesulphonyl chloride ( Hinesburg’s Reagent) which is soluble in dilute solution of NaOH, whereas N,N-Dimethylethanamine does not react.
6.Propanamine reacts with benzenesulphonyl chloride ( Hinesburg’s Reagent) which is soluble in dilute solution of NaOH whereas N-Methyl ethanine reacts but insoluble in dilute solution of NaOH whereas N,N-Dimethylethanamine does not react.
7.Ethanol gives red colour with ceric ammonium nitrate while Ethanoic acid does not.
Or Ethanol gives frutty smell of esters with ethanoic acid and few drops of conc. H2SO4 whereas ethanoic acid does not. (Note- This is ester test)
8.Ethanal gives yellow ppt with a mixture of NaOH and I2 while methanol does not ( Iodoform,s Test)
9.Propanal gives silver mirror or black ppt with Tollen,s reagent( AgNO3 + NH4OH) while Propanol does not.
Or Propanal gives red ppt with mixture of Fehling,s solution A ( solution of CuSO4) and B ( solution of sodium potassium tartarate and NaOH) while Propanol does not.
( Note- Aldehydes gives Tollens test and Fehling,s solution test while ketones does not.)
10.Ethanol gives yellow ppt with a mixture of NaOH and I2 while propanol does not (Note-This is Iodoform,s Test given by compounds having three alpha hydrogen to carbonyl group or three beta hydrogen to alcoholic group)
11.Choloromethane gives white precipitate with AgNO3 but Chlorobenzene does not.
Answers are given in the end
1.What is NFE/SHE ?
2.Explain the variation of conductivity with dilution. or How does conductivity varies with dilution ? Explain the reason for the variation ?
3.Explain the variation of molar conductivity of weak electrolyte with dilution. or How does conductivity of weak electrolyte varies with dilution ? Explain the reason for the variation ?
4.Explain the variation of molar conductivity of strong electrolyte with dilution. or How does conductivity of strong electrolyte varies with dilution ? Explain the reason for the variation ?
5.Explain Kohlrausch law
6.Calculate the Vont hoff’s factor for K4[Fe{CN)6] .
7.What is cell constant ?
8.Why can’t molar conductivity at infinite dilution of weak electrolyte be measured using graphical method ?
9.What are the secondary cells?
10. What are the fuel cells?
11.State advantages and disadvantages of fuel cells.
Answers- 1.The hydrogen electrode at 298 K with pressure of hydrogen is 1 bar and concentration of hydrogen is 1 M is called Standard Hydrogen Electrode / Normal Hydrogen Electrode. 2.Conductivity decrease with dilution because number of ions decreases per unit volume with dilution. ( Conductivity is the conductance of solution of unit volume/ one litre. 3. Molar conductivity of weak electrolyte increases with dilution due to increase in degree of dissociation. 4.Molar conductivity of strong electrolyte increases with dilution due to decrease in interionic attraction as interionic distance increase with dilution. 5.At infinite dilution molar conductivity of weak electrolyte is sum of contribution of molar conductivities of cations and anions which are independent of each other. 6. Von,t Hoff factor = 5/1 =5. 7. Cell constant is the ratio of length between vs area of electrode = L / A 8.Because line of graph never touch molar conductivity axes. 9.The cell which can be reuse again and again by charging. 10. The cell which generate energy from fuel without burning it , is called fuel cell. 11. Advantage of fuel cell-(1) It is pollution free (2) Continuous source of electricity (3) byproduct is water. Disadvantages of fuel cell- It is costly as catalysts is costly.
CHEMIGOD 