Charcoal Cavity Test:

PYQ-2023 Practical Chemistry Q1

Cobalt Nitrate Test:

Flame Test :

PYQ-2024-Practical_Chemistry-Q7

Borax Bead Test :

PYQ-2023 Practical Chemistry Q4

PYQ-2023- d and f block elements-Q6

• Borax bead test is used to identify the nature of cation present in solution by observing the color of the bead. - The color and bead of copper formed during its borax bead test in a hot oxidizing flame is Green when hot and blue when cold
• The compound boric anhydride is not flammable

$$\mathrm{CuSO}_4(\mathrm{aq}) \xrightarrow{\Delta} \mathrm{CuO}(\mathrm{s})+\mathrm{SO}_3(\mathrm{~g})$$

$${CuO}(\mathrm{s})+\mathrm{B}_2 \mathrm{O}_3(\mathrm{~s}) \rightarrow \mathrm{Cu}\left(\mathrm{BO}_2\right)_2$$

Lassaigne’s Test - Sodium fusion test

PYQ-2024-Practical_Chemistry-Q6, PYQ-2024-Genral_Organic_Chemistry-Q6, PYQ-2024-Amines-Q6, PYQ-2023 General Organic Chemistry Q8, PYQ-2023 General Organic Chemistry Q20

Na + C + N → NaCN

Na + C + N + S → NaSCN

$2Na + S → Na_2S$

Na + X → NaX

Test for nitrogen

PYQ-2024-Genral_Organic_Chemistry-Q3, PYQ-2023 General Organic Chemistry Q15

(i) Dumas method: The nitrogen containing organic compound, when heated with copper oxide in an atmosphere of carbon dioxide, yields free nitrogen in addition to carbon dioxide and water. $$ \begin{aligned} & \mathrm{C}_x \mathrm{H}_y \mathrm{~N}_z+(2 \mathrm{x}+\mathrm{y} / 2) \mathrm{CuO} \longrightarrow \mathrm{xCO}_2+\mathrm{y} / 2 \mathrm{H}_2 \mathrm{O}+\mathrm{z} / 2 \mathrm{~N}_2+(2 \mathrm{x}+\mathrm{y} / 2) \mathrm{Cu} \end{aligned} $$

(ii) Kjeldahl’s method:

$$ \begin{aligned} & \text { Organic compound }+\mathrm{H}_2 \mathrm{SO}_4 \longrightarrow\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4 \xrightarrow{2 \mathrm{NaOH}} \mathrm{Na}_2 \mathrm{SO}_4+2 \mathrm{NH}_3+2 \mathrm{H}_2 \mathrm{O} \\ & 2 \mathrm{NH}_3+\mathrm{H}_2 \mathrm{SO}_4 \longrightarrow\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4 \end{aligned} $$

$$ \text { Percentage of } \begin{aligned} \mathrm{N} & =\frac{14 \times \mathrm{M} \times 2\left(\mathrm{~V}-\mathrm{V}_1 / 2\right)}{1000} \times \frac{100}{m} \ & =\frac{1.4 \times \mathrm{M} \times 2(\mathrm{~V}-\mathrm{V} / 2)}{m} \end{aligned} $$

Kjeldahl method is not applicable to compounds containing nitrogen in nitno and azo groups and nitrogen present in the ring (e.g. pyridine) as nitrogen of these compounds does not change to ammonium sulphate under these conditions.

Test for Sulphur

PYQ-2024-Practical_Chemistry-Q8

Lead acetate test

PYQ-2024-Practical_Chemistry-Q5, PYQ-2024-Genral_Organic_Chemistry-Q23

The sodium fusion extract is acidified with acetic acid and lead acetate is added to it. A black precipitate of lead sulfide indicates the presence of sulfur.

Sodium nitroprusside test

Freshly prepared sodium nitroprusside solution is added to the sodium fusion extract, turning the solution deep violet due to formation of sodium thionitroprusside.

$\mathrm{S}^{2-} + [\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NO}]^{2-} \longrightarrow [\mathrm{Fe}(\mathrm{CN})_5 \mathrm{NOS}]^{4-}$

In case, both nitrogen and sulfur are present in an organic compound, sodium thiocyanate is formed which gives blood red color since there are no free cyanide ions.

$\mathrm{Fe}^{3+}+\mathrm{SCN}^{-} \longrightarrow[\mathrm{Fe}(\mathrm{SCN})]^{2+}$

Test for halogens

PYQ-2024-Practical_Chemistry-Q9, PYQ-2023 Aldehyde and Ketone Q10

The sodium fusion extract is boiled with concentrated HNO3 followed by the addition of AgNO3 solution which yields a white (AgCl) or yellow (AgBr or AgI) precipitate if halogen is present.

$NaX + AgNO_3 \longrightarrow AgX+ NaNO_3$

Test for phosphorus

A yellow precipitate (ammonium phosphomolybdate) indicates the presence of phosphorus

$\mathrm{Na}_3 \mathrm{PO}_4+3 \mathrm{HNO}_3 \longrightarrow \mathrm{H}_3 \mathrm{PO}_4+3 \mathrm{NaNO}_3$

$\mathrm{H}_3 \mathrm{PO}_4+21 \mathrm{NaNO}_3+12\left(\mathrm{NH}_4\right)_2 \mathrm{MoO}_4 \longrightarrow\left(\mathrm{NH}_4\right)_3$

$[P(Mo_3 O_{10})_4] + 21 NH $

Analysis of ANIONS (Acidic Radicals) :

PYQ-2024-Practical_Chemistry-Q1

(a) DILUTE SULPHURIC ACID/DILUTE HYDROCHLORIC ACID GROUP:

1. CARBONATE ION $(CO_3^{2-})$

• Dilute $H_2SO_4$ test : A colourless, odourless gas is evolved with brisk effervescence.

$\quad \quad CaCO_3 + H_2SO_4 \longrightarrow CaSO_4 + H_2O + CO_2 \uparrow$

• Lime water/Baryta water $\left(\mathrm{Ba}(\mathrm{OH})_{2}\right)$ test

$\quad \quad CO_2 + Ca(OH)_2 \longrightarrow CaCO_3 \downarrow($ milky $) + H_2O$

$\quad \quad CaCO_3 + CO_2 + H_2O \longrightarrow Ca\left(HCO_3\right)_2$ (soluble) $\rightarrow \Delta$ $CaCO_3 \downarrow + H_2O + CO_2$

2. SULPHITE ION $\left(SO_3 ^{2-}\right)$

Dilute $H_2SO_4$ test :

$\quad \quad CaSO_3 + H_2SO_4 \longrightarrow CaSO_4 + H_2O + SO_2 \uparrow$;

$\quad \quad\mathrm{SO}_{2}$ has suffocating odour of burning sulphur.

Acidified potassium dichromate test : The filter paper dipped in acidified

PYQ-2023- d and f block elements-Q4

PYQ-2023- d and f block elements-Q5

PYQ-2023- d and f block elements-Q9

$\quad \quad K_2Cr_2O_7$ turns green.

$\quad \quad Cr_2O_7^{2-} + 2H^+ + 3SO_2 \longrightarrow 2Cr^{3+}$ (green) $ + 3SO_4^{2-} + H_2O$.

Barium chloride/Strontium chloride solution

$\quad \quad SO_3^{2-} + Ba^{2+} / Sr^{2+} \longrightarrow BaSO_3 / SrSO_3 \downarrow$ (white).

$\quad \quad$ White precipitate dissolves in dilute $\mathrm{HCl}$.

$\quad \quad BaSO_3 \downarrow + 2H^+ \longrightarrow Ba^{2+} + SO_2 \uparrow + H_2O$.

3.SULPHIDE ION $(S^{2-})$

• Dilute $H_2SO_4$ test : Pungent smelling gas like that of rotten egg is obtained.

$$ \mathrm{S}^{2-}+2 \mathrm{H}^{+} \longrightarrow \mathrm{H}_{2} \mathrm{~S} \uparrow $$

• Lead acetate test $\left(CH_3COO\right)_2Pb + H_2S \longrightarrow PbS \downarrow$ (black) $ + 2CH_3COOH$.

• Sodium nitroprusside test: Purple colouration is obtained.

$\quad \quad S^{2-} + [Fe(CN)_5(NO)]^{2-}$ $\rightarrow$ $[Fe(CN)_5NOS]^{4-}$ (violet)

• Cadmium carbonate suspension/ Cadmium acetate solution

$\quad \quad Na_2S + CdCO_3 \longrightarrow CdS \downarrow$ (Yellow) $ + Na_2CO_3$

4.NITRITE ION $\left(NO_2^-\right)$

PYQ-2023- Redox Reaction Q4

• Dilute $H_2SO_4$ test :

$\quad \quad NO_2^- + H^+ \longrightarrow HNO_2 ; \left(2HNO_2 \longrightarrow H_2O + N_2O_3\right)$;

$\quad \quad 3HNO_2 \longrightarrow HNO_3 + 2NO + H_2O ; 2NO + O_2 \longrightarrow 2NO_2 \uparrow$

• Starch iodide test :

$\quad \quad 2NO_2^- + 3I^- + 4CH_3COOH \longrightarrow I_3^- + 2NO \uparrow + 4CH_3COO^- + 2H_2O$

$\quad \quad$ Starch $+\mathrm{I}_{3}^{-} \longrightarrow$ Blue (starch iodine adsorption complex)

5.ACETATE ION $(CH_3COO^-)$

• Dilute $H_2SO_4$ test :

$\quad \quad \left(CH_3COO\right)_2Ca + H_2SO_4 \longrightarrow 2CH_3COOH$ (vinegar like smell) $ + CaSO_4$

• Neutral ferric chloride test :

$\quad \quad 6CH_3COO^- + 3Fe^{3+} + 2H_2O \longrightarrow\left[Fe_3(OH)_2\left(CH_3COO\right)_6\right]^+$(deep red/ blood red colouration) $ + 2H^+$

$\quad \quad [Fe_3(OH)_2(CH_3COO)_6]^+ + 4H_2O \xrightarrow{\text { Boil }} 3Fe(OH)_2CH_3COO\downarrow (\text{brownish red}) + 3CH_3COOH + H^+$

(b)CONC $.H_2SO_4$ GROUP :

1.CHLORIDE ION ( $Cl^-$)

• Concentrated $H_2SO_4$ test :

$\quad \quad Cl^- + H_2SO_4 \longrightarrow HCl$ (colourless pungent smelling gas) + $HSO_4^-$

• $NH_4OH + HCl \longrightarrow NH_4Cl \uparrow$ (white fumes) + $H_2O$.

• Silver nitrate test $\mathrm{Cl}^{-}+\mathrm{Ag}^{+} \longrightarrow \mathrm{AgCl} \downarrow$ (white)

$\quad \quad$ White precipitate is soluble in aqueous ammonia and precipitate reappears with $\mathrm{HNO}_{3}$.

$\quad \quad$ $AgCl + 2NH_4OH \longrightarrow\left[Ag\left(NH_3\right)_2\right]Cl$ (Soluble) + $2H_2O$;

$\quad \quad$ $\left[Ag\left(NH_3\right)_2\right]Cl + 2H^+ \longrightarrow AgCl \downarrow + 2NH_4^+$.

Chromyl chloride test :

PYQ-2023- d and f block elements-Q8

This test is used for the detection of $\mathrm{Cl}^{-}$ions. Example:-

A sample of chlorine-containing salt is heated with potassium chromate $\left(\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7\right)$ and concentrated sulphuric acid $\left(\mathrm{H}_2 \mathrm{SO}_4\right)$. If chloride is present, chromyl chloride is formed, and red fumes are given out. The chromyl chloride test reaction is given as follows: $$ \mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7+4 \mathrm{NaCl}+6 \mathrm{H}_2 \mathrm{SO}_4 \rightarrow 2 \mathrm{CrO}_2 \mathrm{Cl}_2+2 \mathrm{KHSO}_4+4 \mathrm{NaHSO}_4+3 \mathrm{H}_2 \mathrm{O} $$

• For salts such as chlorides of mercury and silver, chromyl chloride test is not applicable. This is because the chlorides of mercury and silver are covalent, and they do not generate $\mathrm{Cl}^{-}$ions.
• The chromyl chloride test is applicable only for compounds having $\mathrm{Cl}^{-}$ionic bonds.

Confirmation for Chromyl Chloride Test

For the confirmation of chromyl chloride, the red vapour needs to dissolve in a solution of sodium hydroxide $(\mathrm{NaOH})$. The solution turns yellow (due to $\mathrm{Na}_2 \mathrm{CrO}_4$ ). $$ \mathrm{CrO}_2 \mathrm{Cl}_2+\mathrm{NaOH} \rightarrow \mathrm{Na}_2 \mathrm{CrO}_4+\mathrm{NaCl}+\mathrm{H}_2 \mathrm{O} $$

$\quad \quad$ $4Cl^- + Cr_2O_7^{2-} + 6H^+$(conc.) $\longrightarrow 2CrO_2Cl_2$ (deep red vapours) + $3H_2O$

$\quad \quad$ $CrO_2Cl_2 + 4OH^- \longrightarrow CrO_4^{2-} + 2Cl^- + 2H_2O$;

$\quad \quad$ $CrO_4^{2-} + Pb^+2 \longrightarrow PbCrO_4 \downarrow$ (yellow)

2.BROMIDE ION $(Br^-)$:

Concentrated $H_2SO_4$ test

$2NaBr + H_2SO_4 \longrightarrow Na_2SO_4 + 2HBr$;

$2HBr + H_2SO_4 \longrightarrow Br_2 \uparrow$ (reddish-brown) + $2H_2O + SO_2$

Silver nitrate test :

$NaBr + AgNO_3 \longrightarrow AgBr \downarrow$ (pale yellow) + $NaNO_3$

Yellow precipitate is partially soluble in dilute aqueous ammonia but readily dissolves in concentrated ammonia solution.

$AgBr + 2NH_4OH \longrightarrow\left[Ag\left(NH_3\right)_2\right]Br + H_2O$

Chlorine water test (organic layer test) :

$2Br^- + Cl_2 \longrightarrow 2Cl^- + Br_2 \uparrow$.

$Br_2 + CHCl_3 / CCl_4 \longrightarrow Br_2$ dissolve to give reddish brown colour in organic layer.

3.IODIDE ION ($I^-$)

Concentrated $H_2SO_4$ test :

• $2NaI + H_2SO_4 \longrightarrow Na_2SO_4 + 2HI$

• $2HI + H_2SO_4 \longrightarrow I_2 \uparrow$ (pungent smelling dark violet) + $2H_2O + SO_2$

Starch paper test iodides are readily oxidized in acid solution to free iodine; the free iodine may than be identified by deep blue colouration produced with starch solution.

$3I^- + 2NO_2^- + 4H^+ \longrightarrow I_3^- + 2NO \uparrow + 2H_2O$

Silver nitrate test : Bright yellow precipitate is formed.

$\mathrm{I}^{-}+\mathrm{Ag}^{+} \longrightarrow \mathrm{Agl} \downarrow$

Bright yellow precipitate is insoluble in dilute aqueous ammonia but is partially soluble in concentrated ammonia solution.

Chlorine water test (organic layer test) :

$2NaI + Cl_2 \longrightarrow 2NaCl + I_2$

$I_2 + CHCl_3 \longrightarrow I_2$ dissolves to give violet colour in organic layer.

4.NITRATE ION $(NO_3^-)$:

• Concentrated $H_2SO_4$ test : Pungent smelling reddish brown vapours are evolved.

$4NO_3^- + 2H_2SO_4 \longrightarrow 4NO_2 \uparrow + O_2 + 2SO_4^{2-} + 2H_2O$

Addition of bright copper turnings or paper pellets intensifies the evolution of reddish brown gas.

$2NO_3^- + 4H_2SO_4 + 3Cu \longrightarrow 3Cu^{2+} + 2NO \uparrow + 4SO_4^{2-} + 4H_2O$

$2NO \uparrow + O_2 \longrightarrow 2NO_2 \uparrow$

$4C$ (paper pellet) + $4HNO_3 \longrightarrow 2H_2O + 4NO_2 + 4CO_2$

Fehling’s Test

PYQ-2024-Aldehydes_and_Ketones-Q2, PYQ-2024-Biomolecules-Q9, PYQ-2024-Aldehydes_and_Ketones-Q2,PYQ-2023 Aldehydes and Ketones Q6

Brown ring test :

PYQ-2024-Practical_Chemistry-Q4, PYQ-2023 p Block Elements Group 14,15,16 Q8

$2NO_3^- + 4H_2SO_4 + 6Fe^{2+} \longrightarrow 6Fe^{3+} + 2NO \downarrow + 4SO_4^{2-} + 4H_2O$

$Fe^{2+} + NO \uparrow + 5H_2O \longrightarrow\left[Fe^I\left(H_2O\right)_5NO^+\right]^{2+}$ (brown ring).

FeCl3 Test

PYQ-2023 Aldehyde and Ketone Q7

Compounds with a phenol group will form a blue, violet, purple, green, or red-brown color upon addition of aqueous ferric chloride. This reaction can be used as a test for phenol groups.

$$ 3 \mathrm{ArOH}+\mathrm{FeCl} 3 \rightarrow \mathrm{Fe}(\mathrm{OAr}) 3+3 \mathrm{HCl} $$

3. Miscellaneous Group :

1. SULPHATE ION $\left(\mathrm{SO}_{4}{ }^{2-}\right)$ :

Barium chloride test :

$ Na_2SO_4 + BaCl_2 \longrightarrow BaSO_4 \downarrow (white) + 2NaCl $

White precipitate is insoluble in warm dil. $\mathrm{HNO}_{3}$ as well as $\mathrm{HCl}$ but moderately soluble in boiling concentrated hydrochloric acid. Lead acetate test :

$ NaSO_4 + (CH_3COO)_2Pb \longrightarrow PbSO_4 \downarrow (white) + 2CH_3COONa $

White precipitate soluble in excess of hot ammonium acetate.

$ PbSO_4 + 2CH_3COONH_4 \longrightarrow (CH_3COO)_2Pb (soluble) + (NH_4)_2SO_4 $

2. PHOSPHATE ION $ (PO_4^{3-})$

Ammonium molybdate test

$$ Na _2HPO _4(aq) + 12(NH _4) 2MoO _4 + 23HNO _3 \rightarrow (NH4) _3PMo _{12}O _{40} \downarrow \text{(canary yellow)} + 2NaNO _3 + 21NH _4NO _3 + 12H _2O $$

Lucas Test

PYQ-2024-Alcohols-Q2, PYQ-2024-Alcohols-3

ANALYSIS OF CATIONS

PYQ-2023 Practical Chemistry Q3

1. AMMONIUM ION $(NH_{4}{ }^{+}) $

$ 2NH_3+Mn^{2+}+H_{2} O_2+H_{2} O \longrightarrow MnO({OH})_2 \downarrow (brown) +2 {NH}_4^{+}$

Nessler’s reagent (Alkaline solution of potassium tetraidomercurate(II)) :

PYQ-2024-Practical_Chemistry-Q3, PYQ-2023- d and f block elements-Q16

$ NH_4^+ + 2 [Hgl_4]^{2-} + 4OH^- \longrightarrow HgO Hg(NH_2)l \downarrow + (brown) + 7I^- + 3H_2O $

$ NH_4^+ + [Co(NO_2)_6]^{3-} \longrightarrow (NH_4)[Co(NO_2)_6] \downarrow yellow $

$ 2NH_4^+ + [PtCl_6]^- \longrightarrow (NH_4)_2 [PtCl_6] \downarrow yellow $

$ NH_4^+ + HC_4H_4O_6^- \longrightarrow NH_4 HC_4 H_4O_6 \downarrow $

$I^{st}$ GROUP $({Pb}^{2+},{Hg}_{2}{ }^{2+},{Ag}^{+}):$

IIA Group $(Hg^{2+},Pb^{2+},Bi^{3+},Cu^{2+},Cd^{2+})$

IIB Group $(As^{3+},Sb^{3+},Sn^{2+},Sn^{4+})$

$ III^{rd} $ Group $(Al^{3+},Cr^{3+},Fe^{3+})$

$ IV^{th} $ Group $(Zn^{2+},Mn^{3+},Ni^{3+},Co^{2+})$

PYQ-2023 Practical Chemistry Q2

$ V^{th} $ Group $(Ba^{2+},Sr^{2+},Ca^{2+})$

$ VI^{th} $ Group

MAGNESIUM ION $\left(\mathrm{Mg}^{2+}\right)$ :

$ Mg^{2+} + NH_3 + (H3PO_4)^{2-} \longrightarrow Mg(NH_4)PO_4 \downarrow ( White )$

$ 5Mg^{2+} + 6CO_3^{2-} + 7H_2O \longrightarrow 2MgCO_3.Mg(OH)_2.5H_2O \downarrow + 2HCO_3^- $

Titan Yellow (a water soluble yellow dyestuff) :

It is adsorbed by $\mathrm{Mg}(\mathrm{OH})_{2}$ producing a deep red colour or precipitate.

Hydrogen peroxide :

• Properties

  • In acidic medium: $H_2O_2 + 2H^+ + 2e^- → 2H_2O$

  • In basic medium :$H_2O_2 + OH^- + 2e^- → 3OH^-$

• Tests :

  • It liberates iodine from potassium iodide in presence of ferrous sulphate

  • Acidified solution of dichromate ion forms a deep blue colour with $H_2O_2$ due to the formation of $CrO_5$,

  • $Cr_2O_7^2- + 4H_2O_2 + 2H^+ → 2CrO_5^­ +5H_2O$

  • With a solution of titanium oxide in conc.$H_2SO_4$, it gives orange colour due to the formation of pertitanic acid.

  • $Ti^4+ + H_2O_2 + 2H_2O → H_2TiO_4 + 4H^+$

  Seperation techniques

PYQ-2023 General Organic Chemistry Q12

PYQ-2023 Some Basic Concept of Chemistry Q8

Chromatography

PYQ-2024-Genral_Organic_Chemistry-Q40, PYQ-2024-Genral_Organic_Chemistry-Q34, PYQ-2024-Genral_Organic_Chemistry-Q28

Column Chromatography: In this method, a sample mixture is loaded onto a column filled with a stationary phase (such as silica gel or a resin). The mobile phase (solvent) flows through the column, and different components of the mixture interact differently with the stationary phase. As a result, they elute at different times, allowing for separation.

Thin-Layer Chromatography (TLC): TLC involves applying the sample mixture as spots on a thin layer of adsorbent material (usually silica gel or alumina) coated on a glass plate or plastic sheet. The plate is then placed in a solvent chamber, and capillary action causes the solvent to move up the plate. Components of the mixture separate based on their affinity for the stationary phase.

Ion-Exchange Chromatography: This technique separates ions based on their charge. The stationary phase contains charged groups that attract or repel specific ions. By adjusting pH or using different eluents, we can selectively release ions from the column.

Distillation

PYQ-2024-Genral_Organic_Chemistry-Q42, PYQ-2024-Genral_Organic_Chemistry-Q18

Distillation is a process used to separate components of a liquid mixture based on differences in their boiling points. The mixture is heated to vaporize the more volatile components, and then the vapor is cooled and condensed back into liquid form. The condensed liquid is collected as the distillate, resulting in the separation of the components based on their different boiling points. Distillation is commonly used in industries such as chemical processing, petroleum refining, and beverage production to purify liquids or separate different components.

Fractional distillation

It is a separation technique used to isolate different components of a mixture based on their boiling points.

Process-

A mixture of two or more miscible liquids (liquids that mix well) is heated.

The substance with the lower boiling point vaporizes first.

Repeated distillations and condensations occur, leading to the separation of the mixture into its component parts.

The more volatile components (those with lower boiling points) vaporize and then liquefy, allowing for separation.

Steam Distillation

PYQ-2024-Genral_Organic_Chemistry-Q44

Steam distillation is a process used to separate volatile compounds from non-volatile compounds. Here is a basic outline of the process:

• Apparatus Setup: The setup typically involves a distillation flask containing the mixture to be distilled, a distillation column (if necessary), a condenser to cool and condense the vapor, and a receiving flask to collect the distillate.
• Introduction of Steam: Water is heated in a separate flask or boiler to produce steam. The steam is then passed through the distillation flask containing the mixture. The steam carries the volatile compounds with it.
• Vaporization and Separation: The mixture is heated, and the volatile compounds vaporize along with the steam. The mixture of steam and vaporized compounds then passes into the condenser.
• Condensation: In the condenser, the hot vapor is cooled and condensed back into liquid form. This condensation separates the volatile compounds from the non-volatile compounds.
• Collection of Distillate: The condensed liquid, now containing the volatile compounds, is collected in the receiving flask. The non-volatile compounds remain in the distillation flask.
• Separation: The distillate is collected and can be further processed if needed to isolate the desired compounds.

Differential Extraction

PYQ-2024-Genral_Organic_Chemistry-Q35

Differential extraction is a technique used in chemistry to separate and purify the components of a mixture based on their solubility in different solvents.

• Preparation of the mixture: The first step is to prepare the mixture containing the components that need to be separated. This can be a solid-liquid mixture or a liquid-liquid mixture.

• Selection of solvents: Choose two solvents that have different polarities and are immiscible with each other. The choice of solvents depends on the solubility of the components in each solvent.

• Extraction process: Add the mixture to a separatory funnel and add one of the solvents. Shake the separatory funnel to allow the components to partition between the two solvents based on their solubility. Allow the layers to separate into distinct phases.

• Separation of layers: After shaking the separatory funnel, let it stand so that the two solvent layers separate into distinct phases. The component of interest will partition into one of the layers based on its solubility in the solvents.

• Collection of layers: Carefully drain the bottom layer (aqueous layer) from the separatory funnel into a separate container. Then drain the upper layer (organic layer) into another container.

• Repeat extraction: If necessary, repeat the extraction process with the same solvent to ensure complete separation of the components.

• Analysis or further processing: After separating the components using differential extraction, the collected layers can be further analyzed or processed using other techniques depending on the specific requirements of the experiment.