Exploring Mixtures and their Separation

Mixtures do ya do se zyada substances ka combination hote hain jo chemically combine nahi hote.

1. Homogeneous Mixtures (Solutions):

• Definition: Wo mixtures jinki composition uniform throughout hoti hai. Components ek dusre mein completely mix ho jaate hain aur separate dikhte nahi hain.
• Particle Size: Particles ka size bahut chhota (less than 1 nm) hota hai, naked eye se visible nahi hote.
• Visibility: Light ka path visible nahi hota (Tyndall effect show nahi karte).
• Separation: Components ko filtration se separate nahi kar sakte.
• Stability: Particles settle nahi hote jab mixture ko undisturbed chhoda jata hai.
• Examples: Salt solution, sugar solution, air, vinegar, brass.

2. Heterogeneous Mixtures:

• Definition: Wo mixtures jinki composition non-uniform hoti hai. Components physically separate dikhte hain aur unki properties different hoti hain.
• Particle Size: Particles ka size bada hota hai (1 nm se zyada).
• Visibility: Light ka path visible ho sakta hai (Tyndall effect show kar sakte hain).
• Separation: Components ko physical methods se separate kiya ja sakta hai.
• Types: Suspensions aur Colloids.
• Examples: Sand aur water ka mixture, oil aur water ka mixture, milk, smoke, fog.

Key Differences:

• Homogeneous: Uniform composition, no visible boundaries, particles cannot be seen.
• Heterogeneous: Non-uniform composition, visible boundaries, particles can often be seen (ya light scatter karte hain).

Solutions:

• Ek homogeneous mixture hota hai do ya do se zyada substances ka.
• Components:
• Solute: Wo substance jo dissolve hota hai, usually lesser amount mein hota hai. (e.g., sugar in sugar solution).
• Solvent: Wo substance jo solute ko dissolve karta hai, usually larger amount mein hota hai. (e.g., water in sugar solution).
• Properties:
• Particles ka size bahut chhota hota hai (approx. 1 nm se bhi kam). Naked eye se nahi dikhte.
• Light ko scatter nahi karte (Tyndall effect show nahi karte).
• Filtration se components separate nahi hote.
• Stable hote hain, particles settle nahi hote.

Concentration of a Solution:

• Ye batata hai ki kitna solute dissolve hai ek given amount of solvent ya solution mein.
• Importance: Labs mein, medicine mein (ORS), agriculture mein (pesticides), food industry mein bahut important hai.

Concentration Express karne ke Methods (Percentage mein):

A. Mass by Mass Percentage (% m/m ya % w/w):

• Mass of solute in 100 grams of solution.
• Formula:

\[\text{Mass by mass percentage} = \frac{\text{Mass of solute}}{\text{Mass of solution}} \times 100\]

• Mass of solution = Mass of solute + Mass of solvent.
• Use: Homogeneous mixtures, packaged food labels (salt, sugar, protein).
• Example: 10g salt + 90g water = 100g solution. % m/m = (10/100) * 100 = 10% m/m.

B. Mass by Volume Percentage (% m/v ya % w/v):

• Mass of solute in 100 millilitres of solution.
• Formula:

\[\text{Mass by volume percentage} = \frac{\text{Mass of solute}}{\text{Volume of solution}} \times 100\]

• Use: Medicines, labs mein jahan volume measure karna easy hota hai. (e.g., 5% glucose solution).
• Example: 5g glucose in 100mL solution. % m/v = (5/100) * 100 = 5% m/v.

C. Volume by Volume Percentage (% v/v):

• Volume of solute in 100 millilitres of solution.
• Formula:

\[\text{Volume by volume percentage} = \frac{\text{Volume of solute}}{\text{Volume of solution}} \times 100\]

• Use: Miscible liquids ke mixtures (e.g., perfumes, cosmetics, vinegar).
• Example: 1mL pesticide in 100mL spray. % v/v = (1/100) * 100 = 1% v/v.

Important Note: Industries mein % w/w commonly use hota hai, jahan weight aur mass ko interchangeably use kiya jata hai.

Solubility:

• Ek given temperature par, maximum amount of solute jo ek fixed quantity (100 mL ya 100 g) of solvent mein dissolve ho sakta hai, uski solubility kehlati hai.
• Factors affecting solubility:
• Temperature:
• Solid solutes ki solubility liquid solvents mein temperature badhane par badhti hai.
• Gaseous solutes ki solubility liquid solvents mein temperature badhane par ghatti hai.
• Nature of solute and solvent: 'Like dissolves like' principle follow hota hai.

Saturated Solution:

• Ek solution jismein aur zyada solute dissolve nahi ho sakta ek particular temperature par, use saturated solution kehte hain.
• Agar aap aur solute add karte hain saturated solution mein, toh wo dissolve nahi hoga aur settle down ho jayega.

Unsaturated Solution:

• Ek solution jismein aur zyada solute dissolve ho sakta hai us particular temperature par, use unsaturated solution kehte hain.

Supersaturated Solution:

• Ek special type ka solution jismein saturated solution se bhi zyada solute dissolve hota hai, usually high temperature par banaya jata hai aur phir carefully cool kiya jata hai. Ye unstable hota hai aur thoda sa disturbance bhi excess solute ko precipitate kar sakta hai.

Solubility Curves:

• Ye solubility vs temperature ka graph hota hai.
• Har substance ki solubility curve different hoti hai, jo batati hai ki temperature change hone par uski solubility kaise change hoti hai.
• Observation: Mostly, solid solutes ki solubility curves upward slope dikhati hain, matlab temperature badhne par solubility badhti hai. Gases ke liye ye downward slope dikha sakti hain.

Crystallization:

• Ye ek process hai jismein pure solid ko uske solution se crystals ke form mein alag kiya jata hai.
• Principle: Substances ki solubility different temperatures par different hoti hai. Impurities solution mein reh jaati hain jab pure substance crystallize hota hai.
• Steps:

1. Solution banana: Impure solid ko suitable solvent mein dissolve karte hain, usually heat karke saturated solution banate hain.
2. Filtration: Hot saturated solution ko filter karte hain taaki insoluble impurities remove ho jayen.
3. Cooling: Filtered solution ko dheere-dheere cool karte hain. Dheere cooling se bade aur well-formed crystals bante hain.
4. Crystal collection: Crystals ko filter karke ya decantation se alag karte hain.
5. Drying: Crystals ko wash karte hain cold solvent se aur dry karte hain.

• Advantages over Evaporation:
• Pure solid milta hai (impurities solution mein reh jaati hain).
• Heat sensitive substances decompose nahi hote.
• Large crystals form hote hain.
• Applications:
• Salt ko seawater se obtain karna.
• Copper sulfate jaise compounds ko purify karna.
• Sugar crystals banana (mishri).

Example: Copper Sulfate Crystals banana (Activity 5.3)

• Copper sulfate ko water mein dissolve karte hain, thoda dilute sulfuric acid add karte hain (impurities ko prevent karne ke liye).
• Saturated solution banate hain by heating.
• Hot solution ko filter karte hain.
• Filter kiye hue solution ko dheere-dheere cool karte hain. Copper sulfate ke crystals form hote hain.
• Crystals ko filter karke dry karte hain.

Distillation:

• Ye method do miscible liquids ko separate karne ke liye use hota hai jinke boiling points mein significant difference (at least 25°C) hota hai.
• Ye ek liquid ko uske dissolved solid se separate karne ke liye bhi use hota hai.
• Principle: Liquid ko heat karte hain, wo vaporize hota hai, vapours ko cool karke condense karte hain, aur phir pure liquid ko collect karte hain.
• Process:

1. Mixture ko distillation flask mein heat karte hain.
2. Lower boiling point wala liquid pehle vaporize hota hai.
3. Vapours condenser se pass hote hain, jahan wo cool hokar liquid mein wapas convert hote hain.
4. Ye condensed liquid (distillate) receiving flask mein collect hota hai.
5. Higher boiling point wala liquid ya solid residue distillation flask mein reh jata hai.

• Applications: Acetone aur water ko separate karna, pure water obtain karna (impure water se).

Fractional Distillation:

• Ye do miscible liquids ko separate karne ke liye use hota hai jinke boiling points mein small difference (less than 25°C) hota hai.
• Principle: Different liquids different temperatures par vaporize hote hain. Fractional column mein multiple vaporization-condensation cycles hote hain.
• Process:

1. Distillation flask ke upar ek fractionating column lagate hain.
2. Column mein glass beads ya plates hote hain jo surface area provide karte hain vapours ke repeated vaporization aur condensation ke liye.
3. Lower boiling point wala component column ke top tak pahunchta hai aur condense ho jata hai, jabki higher boiling point wala component column mein hi condense hokar wapas flask mein gir jata hai.

• Applications:
• Crude petroleum se different fractions (petrol, diesel, kerosene) ko separate karna.
• Air se different gases (oxygen, nitrogen, argon) ko separate karna.

Distillation vs Fractional Distillation:

• Distillation: Large boiling point difference (>= 25°C).
• Fractional Distillation: Small boiling point difference (< 25°C).

Traditional Method: Deg-Bhapka Method (Kannauj):

• Perfumes jaise Mitti ka Ittar banane ke liye use hota hai. Ye traditional distillation technique hai flowers aur other plant parts se fragrances extract karne ke liye.

Paper Chromatography:

• Ye ek technique hai jo mixture ke components ko separate karne ke liye use hoti hai, based on their different solubilities in a solvent and their different affinities for the stationary phase (chromatography paper).
• Principle: Components mixture ke differential adsorption aur differential solubility ke basis par separate hote hain.
• Stationary Phase: Chromatography paper (cellulose).
• Mobile Phase: Solvent (water, alcohol, ya mixture of solvents).
• Process (Activity 5.5):

1. Chromatography paper par pencil se ek line draw karte hain (base line).
2. Us line par mixture ka spot lagate hain (e.g., black ink).
3. Paper strip ko ek container mein rakhte hain jismein solvent hota hai, is tarah ki solvent level spot se neeche ho.
4. Solvent paper par capillary action se upar rise karta hai.
5. Mixture ke components solvent ke saath upar move karte hain, lekin different speeds par.
6. Wo component jo solvent mein zyada soluble hai aur paper se kam adhere karta hai, wo zyada upar move karega.
7. Components separate hokar different spots par dikhte hain.

• Applications:
• Dyes se colors ko separate karna.
• Ink mein different pigments ko separate karna.
• Plant pigments (chlorophyll) ko separate karna.
• Drugs ko blood se separate karna.

Chromatography ka naam: 'Chroma' matlab color aur 'graphein' matlab to write. Pehle ye colored substances ko separate karne ke liye use hota tha.

1. Immiscible Liquids ka Separation (Separating Funnel):

• Definition: Immiscible liquids wo hote hain jo ek dusre mein mix nahi hote aur separate layers banate hain (e.g., oil aur water).
• Principle: Ye method liquids ki different densities par based hai.
• Apparatus: Separating funnel.
• Process (Activity 5.6):

1. Mixture ko separating funnel mein daalte hain.
2. Use undisturbed chhod dete hain taaki liquids separate layers bana len.
3. Denser liquid neeche wali layer banata hai, aur less dense liquid upar wali layer.
4. Funnel ke stopcock ko open karke neeche wali layer ko carefully collect karte hain.
5. Jab neeche wali layer puri nikal jaye, stopcock band kar dete hain.
6. Upar wali layer ko phir alag se collect karte hain.

• Example: Mustard oil aur water ko separate karna. Water (denser) neeche, oil (less dense) upar.

2. Sublimable Solids ka Separation (Sublimation):

• Sublimation: Wo process jismein ek solid directly solid state se gaseous state mein convert hota hai, bina liquid state mein aaye, heating par. Cooling par, gas wapas solid mein convert ho jaati hai (deposition).
• Principle: Mixture mein ek component sublimable ho aur doosra non-sublimable.
• Process (Activity 5.7):

1. Mixture (e.g., camphor aur sand) ko china dish mein rakhte hain.
2. China dish ko heat karte hain.
3. Ek inverted funnel ko china dish ke upar rakhte hain, jiske stem ko cotton plug se band kiya hota hai.
4. Heat karne par, sublimable component (camphor) vapours mein convert hota hai.
5. Ye vapours funnel ki cool inner walls par deposit hokar solid camphor crystals banate hain.
6. Non-sublimable component (sand) china dish mein reh jata hai.

• Examples of sublimable substances: Camphor, naphthalene, ammonium chloride, iodine, dry ice (solid \(CO_2\)).
• Applications: Camphor aur sand ko separate karna, iodine aur salt ko separate karna.

Suspensions:

• Ye ek heterogeneous mixture hota hai jismein solid particles liquid medium mein suspend rehte hain, dissolve nahi hote.
• Properties:
• Particles naked eye se visible hote hain.
• Light ko scatter karte hain, Tyndall effect show karte hain.
• Particles ko filtration se separate kiya ja sakta hai.
• Jab undisturbed chhoda jata hai, toh particles settle down ho jaate hain (unstable).
• Examples: Muddy water, chalk powder in water, sand in water.

Centrifugation:

• Ye ek technique hai jo denser particles ko liquid se separate karne ke liye use hoti hai, by rapidly spinning the mixture.
• Principle: Centrifugal force ka use hota hai. Jab mixture ko high speed par rotate karte hain, toh denser particles tube ke bottom par settle ho jaate hain, aur lighter liquid upar reh jata hai.
• Process:

1. Mixture ko test tubes mein rakhte hain.
2. Test tubes ko centrifuge machine mein place karte hain.
3. Machine ko high speed par spin karte hain.
4. Denser particles centrifugal force ki wajah se bottom par collect ho jaate hain.

• Applications:
• Blood se components (RBCs, plasma) ko separate karna.
• Milk se cream ko separate karna.
• Washing machines mein clothes se water ko squeeze out karna.
• Labs mein fine suspensions ko separate karna.

Coagulation:

• Ye ek process hai jismein fine suspended particles ko clump together karke settle down kiya jata hai, usually ek coagulant add karke.
• Principle: Coagulant particles ke charge ko neutralize karta hai, jisse wo ek dusre ko repel nahi karte aur bade clumps bana lete hain jo gravity ki wajah se settle ho jaate hain.
• Process:

1. Muddy water mein alum (fitkari) jaise coagulant add karte hain.
2. Alum fine suspended particles ko ek saath clump karne mein help karta hai.
3. Ye bade clumps sedimentation se settle ho jaate hain.
4. Phir clear water ko decantation ya filtration se alag kar sakte hain.

• Applications:
• Water purification plants mein muddy water ko clean karna.
• Paneer banane ke liye milk proteins ko coagulate karna (lemon juice ya vinegar se).

Paperfuge: Ek low-cost, hand-powered centrifuge jo remote areas mein blood samples ko separate karne aur diseases detect karne ke liye use hota hai.

Colloids (Colloidal Solutions):

• Ye heterogeneous mixtures hote hain, lekin appear homogeneous karte hain.
• Particles ka size solutions aur suspensions ke beech mein hota hai (1 nm se 1000 nm tak).
• Properties:
• Particles naked eye se visible nahi hote, lekin microscope se dikh sakte hain.
• Light ko scatter karte hain, Tyndall effect show karte hain.
• Particles ko filtration se separate nahi kiya ja sakta.
• Stable hote hain, particles settle nahi hote jab undisturbed chhoda jata hai.
• Components:
• Dispersed Phase: Solute-like component (particles).
• Dispersion Medium: Solvent-like component jismein dispersed phase suspended hoti hai.
• Examples: Milk, blood, ink, fog, smoke, jelly, cheese, shaving cream.

Tyndall Effect:

• Ye light ka scattering phenomenon hai jo colloidal particles ya suspension ke particles show karte hain.
• Observation: Jab light beam (e.g., laser light) solution se pass hoti hai, toh uska path visible nahi hota. Lekin jab colloid ya suspension se pass hoti hai, toh light ka path visible ho jata hai, kyunki particles light ko scatter karte hain.
• Reason: Colloidal particles itne bade hote hain ki wo light ko scatter kar saken, lekin itne chote nahi ki settle ho jayen.
• Everyday Examples:
• Dark room mein small hole se aati hui sunlight ka path visible hona (dust particles ki wajah se).
• Dense tree ke leaves se aati hui sunlight ka path visible hona.
• Fog ya smoke mein headlights ka beam visible hona.

Emulsions:

• Ye colloids ka ek type hai jismein dispersed phase aur dispersion medium dono liquids hote hain.
• Types:
• Oil-in-water (O/W) emulsion: Oil dispersed phase hota hai aur water dispersion medium. (e.g., Milk, vanishing cream).
• Water-in-oil (W/O) emulsion: Water dispersed phase hota hai aur oil dispersion medium. (e.g., Butter, cold cream, body lotion).
• Emulsifying Agents: Wo substances jo emulsions ko stable karte hain, particles ko separate hone se rokte hain. (e.g., Milk mein proteins, soap solution).

Solutions, Suspensions, aur Colloids ka Comparison (Table 5.1):

| S. No. | Property | Solution | Suspension | Colloid | |:-------|:--------------------------|:-----------------------------------------|:-----------------------------------------|:-----------------------------------------| | 1. | Nature | Homogeneous | Heterogeneous | Heterogeneous (appears homogeneous) | | 2. | Particle size | < 1 nm | > 1000 nm | 1 nm - 1000 nm | | 3. | Visibility | Invisible to naked eye | Visible to naked eye | Invisible to naked eye (visible under microscope) | | 4. | Separation by filtration | Cannot be separated | Can be separated | Cannot be separated | | 5. | Settling | Do not settle | Settle down when left undisturbed | Do not settle | | 6. | Tyndall effect | Do not show | Show | Show |