Class 9 Science · Chapter 5
Short answer: "Class 9 Science (Exploration textbook, 2026-27 session) ka Chapter 5 — \"Exploring Mixtures and their Separation\" — mixtures ki classification (homogeneous/heterogeneous), solutions-suspensions-colloids, concentration ke teen formula (mass %, volume %, mass/volume %), solubility, aur separation techniques (evaporation, distillation, fractional distillation, chromatography, sublimation, centrifugation, crystallisation, coagulation) cover karta hai. Neeche poora chapter — intext + exercise solutions step-by-step, formula table, common mistakes aur likely exam questions — mil jayega, jo class 9 science exploration book pdf download ke saath cross-check karke bana hai taaki class 9 science all chapters notes pdf style me revision easy ho."
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Naye class 9 science new syllabus 2026-27 chapter list me (13-chapter \"Exploration\" textbook, NCF-SE 2023 ke hisaab se rewrite hui), Chapter 5 \"Exploring Mixtures and their Separation\" Unit II — Matter ka core hai. Purane \"Is Matter Around Us Pure\" jaisa hi core concept hai, lekin approach naye NCF ke hisaab se real-life application-heavy hai: sugarcane se sugar crystals kaise nikalte hain, malaria detection me paperfuge kaise kaam karta hai, aur Kannauj ki traditional Deg-Bhapka distillation — sab is chapter ka hissa hain.
\nYe exploring mixtures and their separation class 9 notes teen hisson me organised hain: (1) mixtures ke types — homogeneous vs heterogeneous, solutions/suspensions/colloids, (2) concentration ke teen formula (% m/m, % v/v, % m/v) aur solubility curves, (3) practical separation techniques — kaunsa method kab use hota hai aur kyun.
\nChapter 5 poore Class 9-10 Chemistry ki practical backbone hai — board exam me numericals (concentration calculation) aur application-based questions (kaunsi technique use karein) dono yahin se aate hain.
\n"Chapter 5 Summary — 5 Minute Revision
"Chapter 5 \"Exploring Mixtures and their Separation\" ka core takeaway: mixture do ya zyada substances ka bina fixed ratio ke combination hai, jise physical methods se hi alag kiya ja sakta hai (chemical reaction ki zaroorat nahi). Mixtures do type ke hote hain — homogeneous (uniform composition, jaise sugar solution) aur heterogeneous (non-uniform, jaise sand + water); colloids inke beech ka special case hain jinme Tyndall effect dikhta hai.
\nConcentration teen tarike se express hoti hai — mass %, volume %, aur mass/volume % — aur solubility temperature-dependent hoti hai (solid-in-liquid solubility usually temperature ke saath badhti hai, gas-in-liquid ghatti hai). Separation technique ka chunaav mixture ke components ki properties (boiling point, particle size, solubility, density, sublimation ki tendency) par depend karta hai — evaporation/crystallisation solute recover karne ke liye, simple distillation ek volatile liquid ke liye, fractional distillation close boiling points wale liquids ke liye, chromatography closely-related dissolved substances ke liye, sublimation volatile solids ke liye, aur centrifugation bahut fine suspended particles ke liye.
"In-Text Questions — Solutions
Mixture ki definition dijiye aur do udaharan dijiye.
Mixture do ya zyada substances (elements ya compounds) ka aisa combination hai jisme wo apni physical properties retain karte hain aur bina fixed ratio ke milte hain — inhe sirf physical methods se separate kiya ja sakta hai, chemical reaction ki zaroorat nahi hoti.
Udaharan: (i) Namak aur paani ka solution (ii) Mitti aur paani (sand + water suspension).
Homogeneous aur heterogeneous mixture me kya antar hai?
Homogeneous mixture me composition poore mixture me uniform hoti hai — components ko nange aankhon (ya microscope se bhi) alag nahi dekha ja sakta, jaise sugar solution, air.
Heterogeneous mixture me composition non-uniform hoti hai — components alag-alag dikhte hain aur unke beech physical boundary hoti hai, jaise sand + water, oil + water.
Colloid solution aur true solution me Tyndall effect ke aadhar par antar batao.
True solution (jaise sugar solution) me particle size itna chhota hota hai (<1 nm) ki light scatter nahi hoti — light beam invisible rehti hai.
Colloid (jaise milk, starch solution) me particle size 1–1000 nm hota hai jo light ko scatter kar deta hai — is scattering ko Tyndall effect kehte hain, jisse light ka path visible ho jata hai (jaise andhere kamre me projector ki light beam dikhna).
Mass by mass percentage (% m/m) ka formula likhiye aur ek udaharan se samjhaiye.
Mass % = (Mass of solute ÷ Mass of solution) × 100
Udaharan: Agar 15 g namak ko 85 g paani me dissolve kiya jaaye, to mass of solution = 15 + 85 = 100 g.
Mass % = (15 ÷ 100) × 100 = 15%
Ek solution me 20 mL ethanol ko paani me milakar 200 mL solution banaya gaya. Volume percentage nikaliye.
Volume % = (Volume of solute ÷ Volume of solution) × 100
Volume % = (20 ÷ 200) × 100 = 10%
Saturated solution kise kehte hain? Solubility temperature ke saath kaise badalti hai?
Saturated solution wo hoti hai jisme ek fixed temperature par solvent me aur zyada solute dissolve nahi ho sakta (excess solute undissolved reh jaata hai).
Zyadatar solid solutes ki solubility temperature badhne ke saath badhti hai (solubility curve upward), lekin gases ki solubility temperature badhne ke saath ghatti hai — isiliye garam soda flat ho jaata hai.
Simple distillation aur fractional distillation me kab kaunsa use hota hai?
Simple distillation tab use hoti hai jab liquid mixture ke components ke boiling points me bada antar ho (jaise salt solution se paani alag karna).
Fractional distillation tab use hoti hai jab do ya zyada miscible liquids ke boiling points close hon (jaise petroleum refining me crude oil ke fractions, ya ethanol-water mixture) — fractionating column repeated vaporisation-condensation cycles deta hai jisse close boiling points bhi separate ho jaate hain.
Paper chromatography me Rf value kya hai aur ye kis kaam aati hai?
Rf = Distance travelled by solute ÷ Distance travelled by solvent
Rf value har substance ke liye ek characteristic constant hoti hai (fixed solvent aur temperature par) — isse mixture me maujood alag-alag dissolved components ko identify kiya ja sakta hai, jaise ink ke pigments, ya blood/urine sample me dissolved substances.
Sublimation se mixture kaise separate karte hain? Ek udaharan dijiye.
Sublimation wo process hai jisme koi solid seedha gas me badal jaata hai bina liquid state se guzre. Agar mixture me ek component sublime hone wala ho (jaise ammonium chloride, camphor, naphthalene) aur doosra na ho (jaise common salt), to mixture ko garam karne par sublimable component vapour ban kar udd jaata hai aur cool surface par phir se solid ban jaata hai, jabki non-sublimable component peeche reh jaata hai.
Centrifugation ka principle kya hai aur ye kahan use hoti hai?
Centrifugation me mixture ko high speed par ghumaya jaata hai, jisse denser (bhaari) particles centrifugal force ki wajah se bottom me settle ho jaate hain aur lighter particles upar reh jaate hain — ye bahut fine suspended particles ko separate karta hai jo normal filtration se nahi chhant paate.
Use: Blood se plasma alag karna (jaise malaria detection me paperfuge/centrifuge), diagnostic labs me, dairy me cream separate karne me, aur washing machine ke spin-dry cycle me.
Exercise Questions — Solutions (Q1–Q12)
Mixture aur compound me teen antar likhiye.
| Compound | Mixture |
|---|---|
| Fixed ratio me elements/compounds combine hote hain | Koi fixed ratio nahi hota |
| Chemical properties badal jaati hain | Har component apni physical properties retain karta hai |
| Sirf chemical method se separate hota hai | Physical method se separate ho jaata hai |
↔ Table ko side me swipe karein
Ek beaker me 40 g cheeni ko 360 g paani me dissolve kiya gaya. Solution ka mass percentage concentration nikaliye.
Step 1: Mass of solute (cheeni) = 40 g; Mass of solvent (paani) = 360 g
Step 2: Mass of solution = 40 + 360 = 400 g
Mass % = (Mass of solute ÷ Mass of solution) × 100 = (40 ÷ 400) × 100
Mass % = 10%
Answer: Solution 10% (m/m) concentrated hai.
60 mL acetic acid ko paani me milakar 300 mL solution taiyaar kiya gaya. (a) Volume percentage nikaliye. (b) Isme kitna paani mila hoga?
(a)
Volume % = (60 ÷ 300) × 100 = 20%
(b) Volume of water = Total volume − Volume of acetic acid = 300 − 60 = 240 mL
Answer: Concentration 20% (v/v) hai aur 240 mL paani mila gaya hoga.
10 g common salt ko paani me dissolve karke 50 mL solution banaya gaya. Mass/volume percentage nikaliye.
Mass/Volume % = (Mass of solute in g ÷ Volume of solution in mL) × 100
Mass/Volume % = (10 ÷ 50) × 100 = 20%
Answer: Solution 20% (m/v) hai.
Namak aur paani ke mixture ko separate karne ke liye kaunsi technique use karenge aur kyun?
Simple distillation (ya evaporation + condensation) use karenge, kyunki namak ka boiling point paani se bahut zyada hai. Paani ko garam karke vapour banaya jaata hai, jo condenser me thanda hokar wapas liquid (distilled water) ban jaata hai, jabki namak flask me undissolved solid ke roop me reh jaata hai.
Petrol aur mitti ke tel (kerosene) jaise miscible liquids, jinke boiling points close hain, ko kaise separate karenge?
Fractional distillation use karenge. Mixture ko heat karne par lower boiling point wala component pehle vaporise hoga aur fractionating column ke andar repeated vaporisation-condensation cycles se dono liquids alag-alag temperature range par collect ho jaayenge, kyunki simple distillation se close boiling points wale liquids theek se separate nahi ho paate.
Ek mixture me ammonium chloride aur sodium chloride milaye gaye hain. Inhe kaise separate karoge?
Sublimation use karenge. Mixture ko china dish me garam karne par ammonium chloride sublime hokar (solid se seedha gas) upar rakhi thandi surface (funnel/watch glass) par phir se solid ban jaata hai, jabki sodium chloride sublime nahi hota aur china dish me hi reh jaata hai.
Ink me maujood alag-alag rangon ko identify karne ke liye kaunsi technique use karenge? Method briefly likhiye.
Paper chromatography use karenge.
- Chromatography paper par ink ki ek chhoti spot lagate hain (baseline se thoda upar).
- Paper ko solvent (jaise water) me tab tak dubaya jaata hai ki solvent spot ko touch na kare.
- Solvent capillary action se upar chadhta hai aur ink ke alag-alag pigments ko unki solubility ke hisaab se alag-alag speed par le jaata hai.
- Har pigment ek alag position par spot banata hai, jisse unke Rf values nikaal kar unhe identify kiya ja sakta hai.
Suspension, colloid aur true solution me particle size ke aadhar par antar batate hue table banaiye.
| Property | True Solution | Colloid | Suspension |
|---|---|---|---|
| Particle size | < 1 nm | 1–1000 nm | > 1000 nm |
| Appearance | Clear, transparent | Translucent | Opaque, settles down |
| Tyndall effect | Nahi dikhta | Dikhta hai | Dikh sakta hai (par settling ke saath) |
| Filtration | Filter paper se nahi rukta | Ordinary filter paper se nahi rukta | Filter paper se ruk jaata hai |
↔ Table ko side me swipe karein
Doodh se cream kaise alag ki jaati hai? Technique ka naam aur principle likhiye.
Centrifugation technique use hoti hai. Doodh ko high speed par ghumaya jaata hai jisse density ke antar ki wajah se heavier component (skimmed milk) bottom/outer side me settle ho jaata hai aur lighter cream centre/top par alag ho jaati hai.
Kisi mixture me solid particles paani me suspended hain aur bahut chhote (colloidal size ke) hain jo filter paper se nahi rukte. Inhe clear karne ke liye kaunsi additional technique use ki ja sakti hai?
Coagulation use ki ja sakti hai — jisme colloidal particles ko ek electrolyte (jaise alum) daal kar aapas me jama (aggregate) karwaya jaata hai, taaki wo bade particles ban kar settle ho jaayein ya filtration se separate ho sakein. Isiliye water purification me alum use hota hai.
Solubility curve kya batata hai? Ek solid solute ke liye typical trend likhiye.
Solubility curve graph hai jisme X-axis par temperature aur Y-axis par solubility (g solute/100 g solvent at saturation) plot ki jaati hai. Zyadatar solid solutes (jaise potassium nitrate) ke liye curve upward jaati hai — matlab temperature badhne ke saath solubility badhti hai, isiliye garam paani me thanda paani ki tulna me zyada solute dissolve hota hai.
Important Equations — Ek Nazar Me
"| Concept | Formula / Rule |
|---|---|
| Mass percentage (% m/m) | Mass % = (Mass of solute ÷ Mass of solution) × 100 |
| Volume percentage (% v/v) | Volume % = (Volume of solute ÷ Volume of solution) × 100 |
| Mass/Volume percentage (% m/v) | Mass/Volume % = (Mass of solute in g ÷ Volume of solution in mL) × 100 |
| Mass of solution | Mass of solution = Mass of solute + Mass of solvent |
| Retention factor (chromatography) | Rf = Distance travelled by solute ÷ Distance travelled by solvent |
| Choosing separation technique | Boiling point gap bada → simple distillation; boiling points close → fractional distillation; ek component sublime karta hai → sublimation; fine suspended particles → centrifugation; dissolved pigments identify karne hain → chromatography; solution se solid solute wapas lena hai → evaporation/crystallisation |
| Particle size classification | True solution < 1 nm; Colloid 1–1000 nm; Suspension > 1000 nm |
| Solubility trend | Solid solutes: solubility ↑ with temperature (usually); Gas solutes: solubility ↓ with temperature |
↔ Table ko side me swipe karein
"Common Mistakes — Yahan Marks Kat te Hain
- Homogeneous mixture ko galti se pure substance/compound samajh lena — jabki wo do ya zyada substances ka hi mixture hota hai, sirf uniform composition ki wajah se ek jaisa dikhta hai.
- Mass % (m/m), Volume % (v/v) aur Mass/Volume % (m/v) ke formulon ko aapas me mix kar dena — har formula me numerator aur denominator ki units alag hoti hain, question padhkar sahi formula chunna zaroori hai.
- Filtration se colloidal particles bhi ruk jaayenge — ye ek common misconception hai; colloidal particles itne chhote hote hain ki ordinary filter paper se nikal jaate hain, unhe centrifugation ya coagulation se hi separate kiya ja sakta hai.
- Simple distillation aur fractional distillation ko same samajh lena — simple distillation bade boiling-point-gap ke liye hai, fractional distillation close boiling points ke liye jisme fractionating column zaroori hota hai.
- Rf value calculate karte waqt distance galat point se measure karna — Rf hamesha baseline (spot ki original position) se measure hota hai, na ki paper ke bottom edge se, aur Rf value hamesha 1 se kam hoti hai.
- Sublimation ko sirf naphthalene/camphor tak limited samajh lena aur ammonium chloride jaisa common exam example bhool jana — jo mixture-separation numericals me frequently poocha jaata hai.
Board-Style Important Questions
- Short answer: Solute aur solvent ki definition dijiye, ek-ek udaharan ke saath.
- Short answer: True solution aur colloid me Tyndall effect ke aadhar par antar spasht kijiye.
- Numerical: 25 g cheeni ko paani me dissolve karke 250 mL solution banaya gaya. Mass/volume percentage concentration nikaliye aur formula ke saath step-by-step working dikhaiye.
- Conceptual: Paper chromatography ka principle samjhaiye aur Rf value ka formula likhte hue batayein ye kis prakar mixture me maujood substances ko identify karne me madad karta hai.
- Long answer: Ek mixture me sand, common salt aur ammonium chloride mile hain. In teeno ko ek-ek karke alag karne ka poora procedure (used techniques ke naam sahit) likhiye, aur har step ka scientific reason bataiye.
Aksar Poochhe Jaane Wale Sawaal
Class 9 Science Chapter 5 'Exploring Mixtures and their Separation' me kitne separation techniques cover hoti hain?
Ismein mukhya taur par saat techniques cover hoti hain — evaporation/crystallisation, simple distillation, fractional distillation, paper chromatography, sublimation, centrifugation, aur coagulation — har ek ka use mixture ke components ki alag-alag physical properties (boiling point, particle size, solubility, sublimation tendency) par depend karta hai.
Mass %, Volume % aur Mass/Volume % me se kaunsa formula kab use karein?
Agar solute solid hai aur solution bhi mass me diya hai to Mass % use karein. Agar solute aur solution dono liquid volume me diye hain to Volume %. Agar solute mass (g) me hai lekin solution volume (mL) me diya hai — jo common hai jab solid ko liquid me dissolve karte hain — to Mass/Volume % use karein.
Colloid aur suspension me sabse bada practical difference kya hai?
Suspension ke particles gravity ki wajah se settle ho jaate hain aur samay ke saath alag dikhne lagte hain (jaise mitti-paani), jabki colloid ke particles itne chhote hote hain ki wo settle nahi hote aur stable dikhte hain (jaise doodh) — lekin dono me Tyndall effect dikh sakta hai, isliye asli test particle settling aur filtration se hota hai.
Kya Rf value har substance ke liye fixed constant hoti hai?
Rf value ek fixed solvent, temperature aur chromatography paper type ke liye characteristic constant hoti hai — isiliye ise forensic labs me (ink match karna) aur pharma quality-check me substance identify karne ke liye use kiya jaata hai. Lekin agar solvent ya paper badal diya jaaye, to Rf value bhi badal jaayegi.
Exam me 'kaunsi separation technique use karenge' type question kaise approach karein?
Sabse pehle mixture ke components ki properties identify karein — kya wo solid-solid hain ya solid-liquid ya liquid-liquid? Boiling points close hain ya door? Koi component sublime karta hai kya? Particle size kitna chhota hai? Iske baad upar diye formula table (Choosing separation technique row) ke logic se match karein — isse aapka poora reasoning likha jaata hai, sirf technique ka naam nahi, jo application-based questions me better score dilata hai.
Class 9 Science ke baaki chapters ke notes aur questions kahan milenge?
Yahi series ke doosre chapters bhi step-by-step cover hote hain — jaise class 9 science chapter 3 ncert solutions (Cell — the Building Block of Life ke liye cell the building block of life class 9 questions, aur tissues in action class 9 notes Chapter 3 'Tissues in Action' ke liye), motion wale chapters ke liye class 9 science motion chapter formulas aur work energy and simple machines class 9 numericals, atom-related chapters ke liye structure of atom class 9 notes aur atoms and molecules important questions class 9, Sound wale chapter ke liye class 9 science sound chapter important questions, biology wale chapters ke liye reproduction class 9 ncert solutions aur diversity and classification class 9 important questions, aur last chapter ke liye class 9 science earth as a system notes. Poore syllabus ka ek jagah revision chahiye to class 9 science all chapters notes pdf style compilation follow karein.
Class 9 Science — Saare Chapters
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