JEE Advanced 2023 Revision Notes for Practical Organic Chemistry

VSAT 2022

Practical Organic Chemistry Revision Notes for JEE Preparation: Free PDF Download

There are various methods to do a qualitative analysis of organic compounds. There are hurdles that make the analysis of organic compounds quite difficult. In fact, many organic compounds fall into particular classifications. This chapter explains how organic compounds can be qualitatively analyzed using various methods. To understand the concepts of such tests, download and refer to the Practical Organic Chemistry JEE Advanced notes for free from Vedantu.


These notes are explained by the top subject matter experts at Vedantu to provide a better platform for JEE aspirants to learn and revise this chapter for their exams. Students will find the fundamental principles of qualitative analysis methods easier to understand by referring to these notes. They will also be able to resolve their doubts on this chapter on their own with the help of these revision notes.

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JEE Advanced Revision Notes Chemistry Practical Organic Chemistry

Physical Properties:

A knowledge of whether a given compound is liquid or solid (if solid, then crystalline or amorphous) is of great help in its identification (this can by a consulting table of the known compound).


Colour:

The colour of the original sample is noted. Some compound show colour due to impurities, which is frequently produced as a result of their slow oxidation by moist air (freshly distilled anilines is nearly colourless but goes reddish-brown when kept for a longer time), while many other shows colour due to the presence of chromophore groups in them.

A brief summary of conclusions that can be drawn by the observation of colour is given here:

Observation

Inference

Orange-red

Nitroanilines, azo compound, β-naphthoquinone, alizarin

Brown

Higher aromatic amines, diamines

Pink

Naphthol’s

Greenish-yellow

p-nitroso compounds, quinhydrone

Colourless, turning reddish brown or pinkish(due to air oxidation)

Phenol, aniline, aminophenol’s, α-and-β-Naphthylamines

Colourless, turning yellowish or yellow-brown

Anthracene, cinnamic acid, cresols, etc

Colourless

Carbohydrates, aldehydes, ketones, acids, esters, alcohols, ethers, many hydrocarbon

Odour: Many types of organic compounds have characteristics odour and so the ability to detect and remember an Adour is helpful in qualitative analysis, some of the odour characteristics of compounds are given here

Observation

Inference

Odour of better almond

Benzaldehyde, benzonitrile, nitrobenzene

Mouse-like

Acetamide, acetonitrile

Cinnamon-like

Cinnamic acid

Pleasant-fruity

Ester

Pleasant, sweet 

Chloroform, diphenylamine, alcohols

Garlic

Thiophenols, thioalcohols

Phenolic (carbolic)

Many phenols

Pungent, irritating

Lower acid, lower aldehydes, acid halides, thiocids

Camphone-like

Pinacol, hexachloroethane

Intensely disagreeable

Isocyanides

Vinegar-like

Acetic acid, aspirin

Cucumber-like

Chloral

Pyridine-like

Heterocyclic bases

Fish-like

Lower aliphatic amines, side-chain aromatic amine

Odourless

Carbohydrates, aromatic acid, glycerol, solid aliphatic acid, etc

Action of Heat:

Ignition Test: Place a little of the substance (0.1g) on a piece of porcelain and then heat it over a low flame, raising the temperature gradually. Observe whether the compound is volatile; inflammable( if so, nature of the flame); or melts, decomposes or a residue is left, if a residue is left, it is cooled and a drop of distilled ${H_2}O$ is added to the residue and tested with litmus paper (or ph.ph.indicator). then a little of dil.Hcl is added to see whether ay gas is evolved or not

Observation

Inference

Burn with a smoky flame

Aromatic compound

Burn with non-smoky flame

Aliphatic compounds

Melts, darkness swells and then chars with the odour of burnt sugar

Sugar

Chars without melting with the odour of burnt sugar

Starch, inulin, tartaric, citric, or their salts, lactate

Residual ash

Organo metallic compound or metallic salts of acid

Heating with Soda-Lime: Mix well the compound (0.5gm) with powdered soda-lime(1g) in a dry test tube, cover with a layer of soda-lime and heat first gently and then strongly, notice any odour or change in colour.

Observation

Inference

Ammonia or ammoniacal vapour evolved

Ammonium salt of amides, amides, nitriles, aliphatic amino acids or poly nitro-compounds.

Chloroform produced (gives a characteristic odour while cold)

Chloral hydrates

Odour of burnt sugar

Carbohydrates or some aliphatic hydroxyl acid and their salts

Phenolic odour

Phenolic acids or phenyl esters of carboxylic acids

Benzene produced Odour of aromatic amine

Benzene carboxylic acid or their salts

Odour of aromatic amine

Amine salts, aniliids or aromatic amino-carboxylic acid

Colour changes yellow to brown and then black

Many aromatic nitro compounds

Ammonia Odour:
$RCOON{H_4} + NaOH/CaO \to RCOONa + N{H_3} \uparrow  + {H_2}O$

$RCOON{H_2} + NaOH/CaO \to RCOONa + N{H_3} \uparrow$

$RCO - NH - RCO + NaOH/CaO \to RCOONa + N{H_3} \uparrow$


Chloroform Odour

\[CC{l_3}CHO.{H_2}O + NaOH/CaO \to CHCC{l_3} + HCOONa\]

Treatment with conc. ${H_2}S{O_4}$ acid: To a small quantity (0.1g) of the substance contained in a dry test tube, add about 1ml of conc. ${H_2}S{O_4}$ acid and note the reaction first while the mixture is cold and then after it had been gently warmed.

Observation

Inference

Evolution of CO and $C{O_2}$ without charring but the mixture turns yellow

Citric acid and its salts

Rapid charring with effervescence (evolution of Co and/or $C{O_2}$ and $S{O_2}$)

Carbohydrates, tartrates, lactates.

Evolution of evolution of Co and $C{O_2}$ but no blackening

Oxalates

Evolution of pungent vapour but no blackening and no marked effervescence

Many simple carboxylic acids and their salts

Blackening without effervescence

Phenols

Solubility and Reverse Precipitation:

Observation

Inference

Soluble in 5% $NaC{O_3}$ soln. and reprecipitated by dil. HCl acid and not soluble in ${H_2}O$

Aromatic carboxylic acid

Soluble in 5% NaOH soln. (but insoluble in $N{a_2}C{O_3}$Soln. and ${H_2}O$) and reprecipitated by dil. HCI acid.

Water-insoluble phenol

Soluble in dil. HCI (not soluble in ${H_2}O$) and reprecipitated by

NaOH solution.

Organic base

Acidity Test:

Procedure: To obtain a neutral $FeC{l_3}$ soln., add a few drops of$N{H_4}OH$ soln. to $FeC{l_3}$ soln. till a form and filter. Add a few drops of this $FeC{l_3}$ soln. to dilute solution of the substance (neutral solution in case of acids).

Observation

Inference

Intense purple, blue or red colour.

Phenol, phenolic acids, esters and amides

Buff ppt (cleared by dil. HCI but replaced by a white ppt. of free acid.

Aromatic acid and succinate

Greenish colour of ppt.

Catechol, Quinol or ß- naphthol

Red colour (discharges on the addition of dil. HCI )

Amino acids, formic or acetic acids.

Greenish colour (the substance in dil. HCI)

Some amines

Test for Functional Group:

Test of Unsaturation

  1. Addition of ${H_2}$, 1π ≡ mole ${H_2}$

  2. Addition of $B{r_2}/CC{l_4}$ or Bromine water Phenolic compounds give light yellow ppt with $B{r_2}$ water.

  1. Aromatic amines gives ppt with $B{r_2}/{H_2}O$

  2. Bayer's Reagent discharge the colour of dil, cold, alkaline $KMn{O_4}$ to pink or brown

  3. Terminal alkynes gives red/brown ppt with $CuC{l_2}/N{H_4}OH$ due to Copper alkylidene 

  4. Terminal alkyne gives white ppt with tollens reagent Silver alkylidene. 

  5. Undergoes ozonolysis.

Test of OH-Group

  1. Evolves ${H_2}$ gas with Na metal.

  2. Gives red solution with ceric ammonium nitrate.

  3. Gives ester with acetic anhydrides, acid chloride, acids.

  4. Gives halides with $PC{l_5},P{X_3}$anhydride $ZnC{l_2}$ / conc. HCI or $SOC{l_2}$.

  5. Lucas’s test (anhydrous. $ZnC{l_2}$ / Conc. HCI)

30 → Formation of turbidity → immediate

20 → Formation of turbidity within 5 minutes

30 → No turbidity


Test of Phenolic Group

  1. Soluble in NaOH -  Insoluble in $NaHC{O_3}$ (Picric acid is only alcohol soluble in $NaHC{O_3}$)

  2. Phenol gives red colour with alc. $FeC{l_3}$

  3. Phenols — undergoes acetylation & Methylation.

Test of Ether Linkage

  1. Ethers - insoluble in ${H_2}O$

  2. With HI - gives alcohol and alkyl Iodide

  3. With excess HI - only alkyl Iodide

Test of Carbonyl Groups

  1. Phenyl hydrazine &HCI → brown crystalline compound of phenyl hydrazone.

  2. 2,4-DNPH (Brady's reagent) → Red ppt 

  3. $N{H_2}OH/{H^ + }$ → Oxime 

  4. Reduced to alkanes by

Wolf- Kirshner reduction → $N{H_2}N{H_2}/KOH$
Clamminess’s reduction → Zn(Hg)/HCl

Test of Aldehydes Only

  1. Red ppt with Fehling solution → $C{u_2}O$

  2. Red ppt with Benedict's solution → $C{u_2}O$

  3. Silver mirror (Ag) with Tollen's Reagent.

  4. Pink colour with Schiff's reagent.

  5. Aldol condensation - Aldehydes with α−Hydrogen with dil base - NaOH

  6. Cannizzaro Reaction - aldehydes without no α−hydrogen with conc. NaOH/KOH.

Test of Ketones

  1. Wine red colour with sod. Nitroprusside

  2. aliphatic methyl ketones give ppt with $NaHS{O_3}$

  3. On Reduction → gives 20 alcohol.

Test of Carboxylic Acid

(a) With $NaHC{O_3}$ → effervescence of $C{O_2}$

(b) $PC{l_5},PC{l_{3,}}SOC{l_2}$ acid chloride

(c) Amides with NH3/∆

(d) Acetic acid gives blood red colour with $FeC{l_3}$

(e) HCOOH → also gives oxidation with

  • Tollen's Reagent

  • Fehling Solution

  • $HgC{l_2}$

  • $B{r_2}$

Test for Dibasic Acid

  1. Oxalic acid . $CO + C{O_2} + {H_2}O$

  2. Malonic acid → $C{H_3}COOH + CO$

  3. Succinic acid → Succinic anhydrides.

  4. Maleic acid → Maleic anhydrides

  5. Glutaric acid →  Lactones

  6. Adipic acid → Cyclol pentanone

Test of -hydroxy acid → on heating gives Lactides

Test of hydroxy acid → on heating undergoes dehydration to give unsaturated acid.

$R - CH = C{H_2} - COOH + {H_2}O$


Test for Halo Acid

  1. α−halo acids α−hydroxy acid

  2. β−halo acid β−hydro acid 

  3. γ and higher halo acids lactones

Test of  Esters:

  1. Esters are neutral, water-insoluble compound, with fruity smell

  2. Ester on reduction with $LiAl{H_4}$ or $Na/{C_2}{H_5}OH$ gives two moles of alcohol. Ester on hydrolysis (saponification)gives acid and alcohol.

Test of Anhydrides:

  1. Anhydrides react with water to form two acids.

  2. Anhydrides react with $PC{l_5}$ to form acid chloride.

  3. with NH3-form amide and acid,

  4. On reduction with $LiAl{H_4}$-gives two moles of alcohol.

Test of Aliphatic Halogen Compounds

All halides (except vinyl). when heated with aq. NaOH followed by acidification and with AgN03 gives white, light Yellow or dark yellow ppt. 


Test for Amines :

  1. All amines are basic in nature.

  2. All amines are soluble in acids.

  3. Reacts with excess RCI to form quaternary ammonium halides.

  4. With NaNO/Cl or $HN{O_2}$

Reaction Given by Only Primary and Secondary Amine.

  1. 1°& 2° amines are acetylated acid benzoylated.

  2. Evolve ${H_2}$ gas with Na metal.

  3. Gives alkane with G.R.

  4. Gives N-halogenated amines with halogen/NaOH.

Reaction Given by 10 Amines Only.

  1. Carbyl amine test all 1°amines when heated with $CHC{l_3}$ and alc. KOH form isocyanides (Foul smelling odour).

  2. Haloform mustard oil reaction — 1°amine when heated with $C{S_2}$ and $HgC{l_2}$ form isothiocyanates having smell of mustard oil.

Test for Cyanides

  1. Cyanides on reduction with $LiAl{H_4}/Na/{C_2}{H_5}OH$or ${H_2}/Ni$form 1° amines. 

  2.  Cyanides on hydrolysis gives carboxylic acid and ammonia.

Test for Isocyanides

  1. Isocyanides on reduction with $LiAl{H_4}/Na/{C_2}{H_5}OH$or ${H_2}/Ni$form secondary methyl amine. 

  2. Isocyanides on hydrolysis gives p-amines and HCOOH.

Test for Aliphatic Nitro Compound

  1. Reduction with Sn/HCl (acidic medium) -1° amine.

  2. Reduction in neutral medium $Zn/N{H_4}Cl$or $Sn/CaC{l_2}$-Hydroxylamine

On O reaction with $NaN{O_2}$/conc. ${H_2}S{O_4}$
10 − nitro − nitrolic acid − red soln. in NaOH 
20 − nitro −  Pseudonitrol − blue soln.

Alkyl Nitrite : R-O-NO.

  1. On Reduction gives alcohol (Sn/HCl)

  2. On hydrolysis gives alcohol

Test for Amides

  1. Smell of ammonia on heating.

  2. Amides give 10 amine with LiAlH

  3. Amides gives cyanides with ${P_2}{O_5}$

Importance of Practical Organic Chemistry

This chapter focuses on explaining the different types of functional groups that help us to categorize organic compounds. It also explains how these functional groups and elements present in the organic compounds can be tested using various methods.


All these qualitative analysis methods are designed based on the chemical features of organic compounds. These methods have been designed to safely find out the types of elements and functional groups present in such compounds.


Students will be able to learn how the fundamental principles of organic chemistry are used to determine the properties of these compounds. The concepts covered in this chapter will have applications and relevance in organic chemistry, so students can refer to the Practical Organic Chemistry JEE Advanced revision notes to get an overall understanding of the chapter.


This chapter is important as it provides a clear view of the applications of properties of different organic compounds. These properties can be used to recognize the compounds by determining the results of such tests. The detection of elements and functional groups in compounds will give you better insights into such testing methods.


Benefits of Practical Organic Chemistry JEE Advanced Notes PDF

  • These notes are compiled with the sole aim to make the fundamental principles simpler and easily understandable. You will be able to grab the concepts faster and remember them due to the easier format used in these notes.

  • Download the revision notes PDF and refer to it anytime you want. Make your study time more productive by adding these notes to your study material. Before solving questions related to this chapter, read these notes once and you will recall what you have studied easily.

  • The notes have organized the reactions and their outcomes in a specific way. Using this suitable format is a better way to revise and recall the concepts. There is no need to make notes when the experts have done it for you. So you can proceed to solve the sample questions given in the revision notes to check your knowledge.

Download Practical Organic Chemistry JEE Advanced Revision Notes Free PDF

Students can download the free revision notes PDF and complete their study material for this chapter. These notes will help them revise all the topics covered in the chapter very quickly before the exam. Thus they can efficiently use their time to prepare and revise this chapter as well as the entire syllabus. These concise revision notes are highly beneficial for students as they can answer the questions from this chapter easily and score well in the JEE Advanced exam.


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FAQs on JEE Advanced 2023 Revision Notes for Practical Organic Chemistry

1. Why sodium is used for qualitative analysis?

Sodium is a reactive alkaline metal. It is used to check the presence of halogens, nitrogen, and sulphur in organic compounds. Many organic compounds are not soluble in water. Sodium can be used to make salts of such compounds and make them water-soluble and make it easier to perform qualitative analysis.

2. How can we find out the presence of halogen in organic compounds?

Sodium is used in different methods to react with the constituent halogens in an organic compound. Sodium reacts with the halogens to form salts. These salts are then tested to find out which halogen is present.

3. Why should we study qualitative analysis of organic compounds?

The testing methods teach us about the chemical qualities of organic compounds.

4. What is a fusion tube?

It is a small tube made of glass for sodium fusion tests and to do qualitative analysis.

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