Easy way to remember organic reactions and solve conversion questions easily.

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Organic conversions are easy if you are well aware about organic compounds and their reactions. It is quite a challenge to remember all the reactions of all chapters so, summarizing important reactions of different chapters in a flow chart is very effective.

  • It captures the most essential reactions of the chapters in one diagram.
  • Easy for revision.
  • A visual representation has more retention in memory.

Stuck the conversion charts on the wall of your reading room, so you can see reactions frequently and memorize easily.

Conversion Chart of Aliphatic Compounds

  • Organic conversion process need not be a single step every time. You always start with initial reactants and move to intermediate steps , between your initial reactants and the final product. The most important thing that you should master is the art of guessing the Intermediates. Once you guess the correct intermediate you can write the reaction that takes you from reactant to intermediates and then the reaction that takes you from intermediate to the product. For this you have to practice many questions. Generally asked questions in any exam are repeated, so practice of old questions is effective.
  • You can use conversion chart to make the conversion problems easier. Look at the final compound you want to obtain (final product) and initial compound and see the various intermediate compounds formed between reactant and product step by step.

Sample Question :

Q. How would you convert methane to ethanoic acid ?

Search this portion of reactions on the given conversion chart, you can get easily.

How to do an organic conversion easily ?

An organic conversion typically involves two types of transformations

1. Reactions that involve stepping up and down the carbon chain.

2. Reactions that convert functional groups from one to another .

Stepping up and down the carbon chain(series)

Stepping up:

Stepping up the C- chain means that the product has longer carbon chain than that of reactant. Most common methods for stepping up the carbon chain are mentioned below:

1. Reaction of alkyl halide with KCN:

Convert the given compound to an alkyl halide then to a cyanide then to the required organic compound as asked in the question.

Sample Question:

Q. Convert bromomethane to ethanol

You can find this portion in the given conversion chart, so you can do this type of conversions also using conversion chart.

2. Wurtz reaction:

Use this reaction to make product having double number of carbon atoms than in reactant.

3. Using Grignard reagent:

4. Carbonylation reaction [Oxo-process]:

5. Carboxylation reaction:

6. Reaction of HCN with aldehyde to form α-hydroxy acid.

7. Aldol condensation reaction to form β-hydroxy aldehyde or ketone.

Stepping down:

Stepping down the C- chain means that the product has shorter carbon chain than that of reactant. Most common methods for stepping down the carbon chain are mentioned below:

1. Hoffmann’s Bromamide reaction:

Convert the given compound to an amide then let it undergo Hoffmann Bromamide reaction to form amine having one carbon less than that in amide. Then convert the amine to required organic compound as asked in the question.

Sample question :

Q) How would you prepare methanol from ethanoic acid?

You can find this portion easily on the given conversion chart. ( Note: Ethanoic acid can be converted to ethanamide by direct treating with NH3 also)

2. Decarboxylation reaction(reaction with NaOH+CaO):

This reaction can be used to reduce one carbon atom from carboxylic acids and their salts.

3. Ozonolysis:

4. Haloform formation:

Carboxylation, Carbonylation, Decarboxylation reaction and Decarbonylation reaction

Reactions to change the Functional groups

There are various types of reactions to change functional group . Be familiar with basic conversions such as :

  • Reduction
  • Oxidation
  • Halogenation
  • Hydrolysis
  • Nitration
  • Carboxylation ( used to step up a carbon chain also)
  • Alkyl Cyanide formation(used to step up a carbon chain also)
  • Ozonolysis
  • Dehydration
  • Dehydrohalogenation
  • Decarboxylation, etc……
  • For more common conversions see the given conversion chart and try to remember. Eg. aq. KOH is used to convert haloalkane to alcohol.PCl5 is used to convert alcohol to haloalkane and carboxylic acid to acid chloride. Etc…
  • Grignard reagent is a versatile reagent which can be used for many conversions.
  • Simple oxidation – reduction reactions can be useful to convert alcohol to aldehyde / ketone to carboxylic acid and vice- versa.

Some common reagents and their role

Conversion Practice Chart of Aliphatic Compounds

Now , examine yourself by filling the chart and then compare your chart with chart attached above.

Ideas to solve word problems in organic chemistry

Sample question:

Q) An alcohol “A” reacts with PCl5 to give ” B”. “B” reacts with alc. KOH to give “C” , “C” on ozonolysis followed by hydrolysis forms methanol as major product. Identify A,B and C.

To solve such type of problems, at first make a rough sketch of reaction putting given informations as :

We know that, alcohol reacts with PCl5 to give chloro alkane which reacts with alc.KOH ( dehydrohalogenation reaction) to give an alkene and alkene on ozonolysis followed by hydrolysis forms aldehyde or ketane. Hence, we can write above reaction as :

Now, if you have basic knowledge about simple organic reactions you can easily go back from product(methanal) to ‘A’ as:

  • Compound “C” on ozonolysis gives methanal. Here, you must have knowledge about ozonolysis reaction. Actually two carbonyl compounds are formed by ozonolysis and according to question both must be methanal. Thus, ‘C’ (i.e alkene) should have two carbon atoms, which is ‘Ethene’.
  • Now ‘B’ should be chloroalkane having two carbon atoms i.e. ‘chlorothane’. Finally, ‘A’ must be alcohol having two carbon atoms, i.e. ‘Ethanol’.

Hence the reaction sequence is:

You have to be confident when doing organic conversions. For this, start with the basic conversions, they help you to solve the higher level conversions. Learn basic reactions, keep reading the reaction charts which you have or I have attached here and practice as much as possible. You must know some tricks mentioned above or you can also form some hacks and tricks by practice.

Conversion Chart of Aromatic Compounds

Conversion Practice  Chart of Aromatic Compounds

Now,  fill the chart and compare your chart with the chart attached above.

I hope it helps you . If any confusion comment below or message us.

Practice Questions

  1. Compound ‘A’ with the molecular formula C4H9Br is treated with aq. KOH solution. The rate of this reaction depends upon the concentration of the compound ‘A’ only. When another optically active isomer ‘B’ of this compound was treated with aq.KOH solution, the rate of reaction was found to be dependent on concentration of compound and KOH both.
  • Write down the structural formula of both compounds ‘A’ and ‘B’.
  • Out of these two compounds, which one will be converted to the product with inverted configuration?
  1. An alkene ‘A’ (Mol. formula C5H10) on ozonolysis gives a mixture of two compounds, ‘B’ and ‘C’. Compound B’ gives positive Fehling’s test and forms iodoform on treatment with I2and NaOH. Compound C’ does not give Fehling’s test but forms iodoform. Identify the compounds A, B, and C. Write the reaction for ozonolysis and formation of iodoform from B and C.
  2. An aromatic compound “A’ (Molecular formula C8H8O) gives a positive 2, 4-DNP test. It gives a yellow precipitate of compound ‘B’ on treatment with iodine and sodium hydroxide solution. Compound A’ does not give Tollen’s or Fehling’s test. On severe oxidation with potassium permanganate forms a carboxylic acid ‘C’ (Molecular formula C7H602), which is also formed along with the yellow compound in the above reaction. Identify A, B and C and write all the reactions involved.
  3. When liquid ′A′ is treated with a freshly prepared ammonical silver nitrate solution, it gives a bright silver mirror. The liquid forms a white crystalline solid on treatment with sodium hydrogen sulphite. Liquid ′B′ also forms a white crystalline solid with sodium hydrogen sulphite, but it does not give a test with ammoniacal silver nitrate. Which of the two liquids is aldehyde? Write the chemical equations of these reactions also.
  4. A primary amine, RNH2 can be reacted with CH3-X to get secondary amine, R-NHCH3but the only disadvantage is that 30 amine and quaternary ammonium salts are also obtained as side products. Can you suggest a method where RNH2 forms only 20 amine?
  5. A hydrocarbon ‘A’, (C4H8) on reaction with HCl gives a compound ‘B’, (C4H9CI), which on reaction with 1 mol of NH3gives compound ‘C’, (C4H11N). On reacting with NaNO2 and HCI followed by treatment with water, compound ‘C’ yields optically active alcohol, ‘D’. Ozonolysis of ‘A’ gives 2 moles of acetaldehyde. Identify compounds ‘A’ to ‘D’. Explain the reactions involved.
  6. An organic compound (A) having molecular formula C3H7Cl on reaction with alcoholic solution of KCN gives compound B. The compound B on hydrolysis gives compound C. C on reduction with H2 / Ni gives 1-aminobutane. Identify A, B and C.
  7. An alcohol A (C4H10O) on oxidation with acidified potassium dichromate gives carboxylic acid B(C4H8O2). Compound A when dehydrated with conc. H2SO4 at 443K gives compound C. Treatment of C with aqueous H2SO4 gives compound D(C4H10O) which is an isomer of A. Compound D is resistant to oxidation but compound A can be easily oxidised. Identify A,B, C and D and write their structures.
  8. An organic compound A having molecular formula C6H6O gives a characteristic colour with aqueous FeCl3. When A is treated with NaOH and CO2 at 400K under pressure, compound B is obtained. Compound B on acidification gives compound C which reacts with acetyl chloride to form D which is a popular pain killer. Deduce the structure of A, B, C and D. What is the common name of Drug D?
  9. An ether A(C5H12O) when heated with excess of hot concentrated Hl produced two alkyl halides which on hydrolysis from compounds B and C. Oxidation of B gives an acid D whereas oxidation of C gave a ketone E. Deduce the structures of A,B, C,D and E.
  10. An organic compound A, molecular formula C9H10O forms 2,4-DNP derivative, reduces Tollen’s reagent and undergoes Cannizzaro reaction. On vigorous oxidation, it gives 1,2-benzene dicarboxylic acids. Identify A.

Ans: The compound A will be 2-Ethylbenzaldehyde.

  1. A compound X (C2H4O) on oxidation gives Y (C2H4O2). X undergoes haloform reaction. On treatment with HCN, X forms a product Z which on hydrolysis gives 2-hydroxypropanoic acid. Write down the structures of X and Y.
  2. An alkene (A) with molecular formula (C7H14) on ozonolysis yields an aldehyde. The aldehyde is easily oxidized to an acid (B). When B is treated with bromine in presence of phosphorous it yields a compound (C) which on hydrolysis gives a hydroxyl acid (D). This acid can also be obtained from acetone by the reaction with hydrogen cyanide followed by hydrolysis. Identify A, B, C and D and write the chemical equations for the reactions involved.
  3. An organic compound A (C2H3N)is used as a solvent of choice for many organic reactions because it is not reactive in mild acidic and basic conditions. Compound A on treatment with Ni/H2 forms B. When B is treated with nitrous acid at 273 K, ethanol is obtained. When B is warmed with chloroform and NaOH, a foul smelling compound C is formed. Identify A, B and C.
  4. An organic compound A C3H6O2 on reaction with ammonia followed by heating yield B. Compound B on reaction with Br2and alc. NaOH gives compound C (C2H7N). Compound C forms a foul smelling compound D on reaction with chloroform and NaOH. Identify A, B, C, D and write the equations of reactions involved.
  5. Compound ‘A’ of molecular formula C5H11Br yields a compound ‘B’ of molecular formula C5H12O when treated with aqueous NaOH. On oxidation, the compound ‘B’ yields a ketone ‘C’. Vigorously oxidation of ketone yields a mixture of ethanoic and propanoic acids. Deduce the structures of ‘A’, ‘B’ and ‘C’.
  6. A compound ‘A’ with molecular formula C5H12O, on oxidation forms compound ‘B’ with molecular formula C5H10O. The compound ‘B’ on reduction with amalgamated zinc and HCl gives compound ‘C’ with molecular formula C5H12. Identify A, B and C. Write down the chemical reactions involved.
  7. An organic compound A having the molecular formula C3H8O on treatment with copper at 573K gives B, B does not reduce Fehling solution, but gives positive iodoform test. Write down the structural formulae of A and B.
  8. An organic compound a having molecular formula CH4O on treatment with P/I2 gives a compound B. the compound B on further treatment with KCN and on subsequent reduction gives compound C. the compound C on treatment with HNO2 gives another compound D, which responds to the iodoform test. Identify the compounds A, B, C and D. Explain all reactions.
  9. A ketone A, which undergoes haloform reaction gives compound B on reduction. B on heating with conc. H2SO4 gives compound C, which forms mono-ozonide D. D on hydrolysis in the presence of Zn dust gives only acetaldehyde. Identify A, B, C and D. Write the reactions involved.
  10. An organic compound A having molecular formula CH3CN on reduction give another compound B. B on treatment with HNO2 give ethyl alcohol and on warming with CHCl3 and KOH (alcoholic) gave an offensive smelling substance C. Identify A,B and C. Write down the equation involved.
  11. An optically inactive compound (A) having molecular formula C4H11N on treatment with HN02 gave an alcohol, (B). (B) on heating with excess of conc. H2SO4 at 440K gave an alkene (C) . (C) on treatment with HBr gave an optically active compound (D) having molecular formula C4H9Br . identify A,B,C and D and write down their structural formulae. Also write the equation involved.

{ Ans. A=C4H9NH2 B=C6H9OH C=but-1-ene D= 2-bromobutane }

  1. An organic compound A on treatment with ethyl alcohol gives a carboxylic acid B and a compound C. Hydrolysis of C under acidic conditions gives B and D. Oxidation of D with KMnO4 also gives B. B upto heating with Ca(OH)2 gives E (molecular formulae C3H6O). E Does not gives Tollen’s test and does not reduce Fehling solution , but forms  2,4-dinitrophenyl hydrazone. Identify A,B,C,D and E.

{Ans.  A= (CH3CO)2O    B= CH3COOH   C= CH3COOC2H5     D=C2H5OH      E=CH3COCH3} 

  1. Compound A (C6H12O2) on reduction with LiAlH4 yielded two compounds B and C. The compound B on oxidation give D, which on treatment with aqueous alkali and subsequent heating furnished E. The latter, on catalytic hydrogenation gave C. The compound D was  oxidized further to gave F, which was found to be a monobasic acid (mol.wt= 60). Deduce the structures of A,B,C,D and E.

{Ans. A=CH3CH2CH2COOCH2CH3     B=CH3CH2OH      C= CH3CH2CH2CH2OH   D=CH3CHO  E=CH3CH=CHCHO  F: CH3COOH}

  1. An alkene A on ozonolysis yield acetone and an aldehyde. The aldehyde is easily oxidized to an acid B. when B is treated with bromine in the presence of phosphorus, it yield compound C, which on hydrolysis gives a hydroxyl acid D. This acid can be obtained from acetone by the reaction with hydrogen cyanide followed by hydrolysis. Identify the compound A,B,C and D.
  2. Compound A(C5H10O) forms phenyl hydrazone, gives negative Tollen’s and iodoform tests, and is reduced to pentane. What is the structure of the compound A?

{Ans. CH3CH2COCH2CH3, Pentan-3-one}

  1. A ketone A gives iodoform on reaction with iodine, and sodium hydroxide. A on reduction gives B which on heating with sulphuric acid gives C. Con ozonolysis gives acetaldehyde and acetone . Identify A,B and C.

{Ans. A= 3 methylbutan-2-one   B= 3-methylbutan-2-ol   C= 2-methylbut-2-ene}

28. An organic compound (A) which reduces Tollen’s reagent, on oxidation with potassium permanganate formed compound (B) which has same number of carbon atoms as (A). (B) reacts with Na2CO3 to give CO2. (B) on reaction with ethanol in presence of sulphuric acid formed a compound having molecular formula C4H8O2 (C). Identify A, B, C with suitable reactions and their IUPAC names.

29. Complete the reaction cycle with suitable reaction conditions.

30. Predict the reagent or the product in the following reaction sequence.

31. A liquid of molecular formula C7H6O forms an oxime, reduces Tollen’s reagent and undergoes Clemmensen reduction to give toluene. Explain the reaction involved and write the structural formula of this liquid.

32. Compound ‘A’ C5H12O reacts with K2Cr2O7/H+ to form ‘B’ C5H10 Compound ‘B’ reacts with 2,4-dinitrophenylhydrazine to form a yellow solid but does not give a silver mirror when treated with Tollen’s reagent or a precipitate of iodoform when heated with basic solution of I2 . Draw the structures of ‘A’ and ‘B’. Show the reactions involved.

33. An organic compound (A) on catalytic reduction gives (B), (B) on chlorination gives (C), (C) on heating with sodium metal in presence of ether gives (D), (D) on chlorination gives 2-chlorobutane as the major product. Give the names for (A), (B) (C) and (D) with reaction.

34. Compound (A), C7H8O, does not react with sodium metal. When (A) is treated with Hl, two compounds (B) and (C) are formed. Compound (B) reacts with sodium to produce hydrogen, and also forms a salt with NaOH. Compound (B) can be brominated, and the major product contains three bromine atoms. Compound (C) contains iodine. Compound (C) reacts with magnesium in dry ether to form a Grignard reagent. The Grignard reagent reacts with CO2, followed by acid hydrolysis to form acetic acid. Identify (A), (B) and (C). Show the reactions involved.

35. A hydrocarbon (A) gives a positive Baeyer’s test. When (A) is treated with conc. sulphuric acid and water, 2-butanol is produced. Ozonolysis of (A) gives propanal and methanol. What is the structure of (A) ? Write equations for all reactions.

36. Compound (A) having molecular formula (C3H602) which upon ammonolysis gives (B). (B) when heated with Br2 in presence of KOH, gives (C). (C) when heated with nitrous acID gives compound (D) which gives positive iodoform test. (D) again on oxidation gives compound (E) which when reacted with ethyl alcohol gives pleasant smell. Find (A), (B), (C) (D) and (E).

37. A compound (A) reacts with thionyl chloride to give compound (B). Compound (B) react with magnesium to form a Grignard reagent which is treated with acetone and the product hydrolysed to give 2-methyl-2-butanol. What are the structural formulae of (A) and (B)?

38. Compound (A) C6H12 decolorizes bromine, but gives no reaction with sodium metal or phenylhydrazine. Ozonolysis of (A) gives two compounds, (B) and (C), both react with phenylhydrazine. Compound (B) gives positive Tollens’ and iodoform tests. Compound (C) has molecular weight of 72. Suggest structures for (A), (B) and (C). Give equations for all reactions.

39. The compound (A), C3H8O, acts as a Lewis base in its reaction with conc. HBr to give (B) ,C3H7 On treatment with conc. sulphuric acid, (A) undergoes an elimination reaction to give the hydrocarbon (C). When (C) is reacted with concentrated HBr the result product (D), C3H7Br ,which is formed in accordance with the Markovnikov’s rule and is isomer with (B). Deduce the structures of (A), (B), (C) and (D) and explain the reactions.

40. Compound (A), C6H12O, gives the following results:

(a) (A) gives positive test with hydroxylamine.

(b) (A) does not react with Tollen’s reagent.

(c) (A) on catalytic hydrogenation gives (B), C6H14O.

(d) (B) on treatment with conc. H2SO4 gives (C), C6H12.

(e) (C) on ozonolysis gives two compounds, (D)C3H6O and (E) C3H6O.

(f) (D) gives a negative Tollens’ test and +ve iodoform test.

(g) (E) gives a negative iodoform test and +ve Tollens’ test.

What are the structure of (A) to (E)? Explain the reactions.

41. An aliphatic compound (A) reacts with SOCl2 to give (B). The compound (B) is heated with ammonia to produce (C). The compound (C) is further heated with Br2/KOH to yield (D). The compound (D) gives (E) when trailed with NaN02/HCI at low temperature. The compound (E) is primary alcohol which gives positive iodoform test. Identify (A), (B), (C), (D) and (E). Write reactions involved.

42. An amine (A) has formula C3H9 When (A) is treated with nitrous acid at 0 — 5°C, a reaction takes place and an oily yellow layer separates from the reaction mixture. What is (A)? Give an equation for the reaction.

43. An organic compound (A) having molecular formula CH40 on treatment with red phosphorus and iodine gives a compound (B). The compound (B) on treatrnent with KCN followed by reduction gives a compound (C). The compound (C) on treatment with nitrous acid at cold condition gives a compound (D) which gives positive iodoform test. Identify the compounds (A), (B), (C) and (D) and give all reactions.

44. An unknown ester C5H1202 was hydrolysed with water and acid to give carboxylic acid (A) and alcohol (B). Treatment of (B) with PBr3 gave an alkyl bromide (C). When (C) was treated with KCN, a product (D) was formed which on acid hydrolysis gave the carboxylic acid (A). Give the structure and name of the original ester. Identify (A), (B), (C) and (D) and write equations for the reactions involved.

45. An organic compound (A) when reacts with alc. KOH gives (B) which on ozonolysis gives (C). This compound on Clemmensen reduction gives propane. The compound (C) also give iodoform test. Compound (D) is obtained when (C) urdergoes Aldol condensation. On reaction of (C) with 2,4 -DNP reagent gives compound (E). Identify (A), (B), (C), (D) and (E).

46. An organic compound (A) reacts with HCN to give (B). On hydrolysis of (B) in acidic medium gives (C). Compound (A) also produces propane when treated with zinc-amalgam and HCI. Identify (A), (B) and (C) with reaction and give their IUPAC names. What product would you expect when (A) is treated with trichloromethane in alkaline medium?

47. An organic compound (A) reacts with PBr3 to give (B). Compound (B) produces (C) when heated with alc. KOH. The compound (C) undergoes ozonolysis to yield ethanal and methanal as the products. The compound (A) responses iodoform test. Identify (A), (B), (C) and write reactions involved. How is (A) obtained from CH3MgBr?

48. Compound (A), C5H10O gives the following results:

  • Treatment with 2,4-DNP gives a coloured precipitate.
  • It gives negative Tollen’s test.
  • It gives positive iodoform test.

Suggest two structures for (A) that are consistent with these facts.

49. Identify A, B, C, D and E in the following reaction.

50. Prepare a sequence of reactions from the given list with necessary conditions and reagents.

Convert:

  1. 1-bromopropane to 2- bromopropane and vice- versa.
  2. 1- propanol to 2- propanol and vice versa.
  3. Methanamine to ethanamine and vice versa.
  4. Phenol to anisole(methoxy benzene) and vice versa.
  5. Ethoxy ethane to methoxy ethane.
  6. Phenol/aniline to azo-dye.
  7. Ethanal/ ethanol to 3-hydroxy butanal.
  8. Ethanol to 2- hydroxy propanoic acid.
  9. Propanone(acetone) to 2-hydroxy-2-methyl propanoic acid.
  10. Phenol to toluene.
  11. Ethanol to propanol/ propanoic acid.
  12. Methanamide to ethanamine.

References

  • Finar, I. L., Organic Chemistry, Vol. I and Vol. II, Prentice Hall, London, 1995.
  • Bahl, B.S., A., Advanced organic Chemistry, S. Chand and company Ltd, New Delhi, 1992.
  • Sharma, M. L., Chaudhary, P.N., A Text Book of B.Sc. Chemistry, Second Edition, Ekta Books, Kathmandu, 2004.
  • Ghosh, S.K., Advanced General Organic Chemistry, Second Edition, New Central Book Agency Pvt. Ltd, Kolkatta, 2007.