Class 8 Science Chapter 9: The Amazing World of Solutes, Solvents, and Solutions (Hinglish Notes)
Ye chapter 5 lines mein
The Amazing World of Solutes, Solvents, and Solutions batata hai ki ORS har ghoont mein ek jaisa kyon lagta hai: vilay (solute) vilaayak (solvent) mein barabar ghulkar vilayan (solution) banata hai. Ek had tak hi ghulta hai, aur taapmaan ye had badalta hai. Doosra hissa ghanatva (density) par hai: ikai aayatan ka dravyamaan, dravyamaan aur aayatan kaise naapein, aur cheezein kyon tairti ya doobti hain.
Ye chapter kis baare mein hai?
Ghar ka bana ORS pehle ghoont mein bhi waisa hi lagta hai jaisa aakhri mein; kabhi ek ghoont namkeen aur agla meetha nahi hota. Aisa isliye hai kyunki cheeni aur namak paani mein barabar fail jaate hain. Chapter aise mishranon ko samajhta hai: kya kismein ghulta hai, kitna ghul sakta hai, aur garmi ka us par kya asar hota hai. Doosra hissa poochhta hai ki chaawal dhote samay bhoosi kyon tairti hai aur daane kyon doobte hain, jisse ghanatva aur dhyaan se dravyamaan aur aayatan naapne ki baat aati hai.
Vilay, vilaayak aur vilayan
Paani mein namak ya cheeni milaao to uniform mishran banta hai, jise vilayan kehte hain. Paani mein chalk powder, ret ya buraada milaao to hisse dikhte rehte hain, isliye ye non-uniform mishran hain, vilayan nahi. Jab thos drav mein ghulta hai, thos vilay hota hai aur drav vilaayak: vilay + vilaayak → vilayan. Gulab jamun ki chashni mein paani se kahin zyada cheeni hoti hai, phir bhi cheeni hi vilay hai. Jab do drav milte hain, kam maatra wala vilay kehlaata hai. Hawa, gaison ka uniform mishran, bhi ek vilayan hai.
Kitna ghul sakta hai?
Aadhe glass paani mein ek-ek chammach namak daalo (Activity 9.1). Shuru mein har chammach gaayab ho jaata hai; kuch ke baad, kitna bhi hilaao, thoda namak neeche reh jaata hai. Paani ek had tak hi namak rakh sakta hai. Jo vilayan aur ghol sake wo asantript hai; jab faaltu vilay neeche baithne lage, wo us taapmaan par santript hai. Tay maatra ke vilayan mein vilay ki maatra uski saandrata hai: kam vilay se tanu aur zyada se saandra vilayan banta hai, aur ye shabd sirf tulna karte hain. Tay maatra ka vilaayak jitna sabse zyada vilay le sake, wo uski ghulansheelta hai. Padho ghulansheelta kya hai.
Taapmaan aur ghulansheelta
Ek demonstration (Activity 9.2) mein 20 °C ke 50 mL paani mein baking soda tab tak ghola jaata hai jab tak kuch bina ghule na bache. 50 °C tak garam karne par bacha hua ghul jaata hai aur aur daala ja sakta hai; 70 °C par aur bhi zyada ghulta hai. Zyaadatar thos padaarthon ki ghulansheelta taapmaan ke saath badhti hai, isliye garam karne par santript vilayan asantript ban jaata hai. Gaisein ulta karti hain. Oxygen paani mein bahut thodi ghulti hai, phir bhi yahi ghuli oxygen machhliyon aur jal-paudhon ko zinda rakhti hai, aur thanda paani garam paani se zyada oxygen rakhta hai.
Ayurveda, Siddha aur doosri Bharatiya chikitsa paddhatiyon mein paani lambe samay se mukhya vilaayak raha hai, aur tel, ghee aur doodh bhi dawaaiyon ke liye istemaal hote rahe. Rasaayanshaastri Asima Chatterjee ne aushadhiya paudhon se yaugik nikaalne ke liye vilaayakon ka upyog kiya aur mirgi aur malaria ki dawaaiyaan viksit ki.
Ghanatva kya hai?
Ek hi size ki lakdi ki chhadi aur lohe ki chhad haath mein bilkul alag lagti hain. Bheed bhari bus aur lagbhag khaali bus, ya ghana jungle aur chhitra jungle, yahi baat dikhaate hain: padaarth kitna kasa hua hai. Ghanatva ikai aayatan mein dravyamaan hai, ghanatva = dravyamaan ÷ aayatan. Ye kisi cheez ke aakaar ya size par nirbhar nahi karta. Iski SI unit kg/m³ hai, aur chhoti maatra ke liye g/mL ya g/cm³ suvidhajanak hain. 1 mL paani ka dravyamaan lagbhag 1 g hai, isliye paani ka ghanatva lagbhag 1 g/mL hai. Saapeksh ghanatva kisi padaarth ki tulna paani se karta hai: 10 cm³ mein 27 g wala aluminium 2.7 g/cm³ hai, isliye uska saapeksh ghanatva 2.7 hai. Padho ghanatva kya hai.
Dravyamaan aur aayatan ka maap
Dravyamaan balance se naapa jaata hai. Digital balance par pehle dekho ki display zero dikha raha hai, pan par saaf watch glass rakho, zero par laane ke liye tare dabao, phir cheez rakho; ek patthar 16.400 g dikha sakta hai. Dravyamaan padaarth ki maatra hai, gram ya kilogram mein; bhaar Prithvi ka kheechaav hai, newton mein. Drav ka aayatan measuring cylinder se naapte hain: do number wale nishaanon ke antar ko chhote bhaagon ki sankhya se bhaag dekar sabse chhoti reading nikaalo, aankh meniscus ke star par rakho, aur paani ke liye uska nichla hissa padho. Cuboid ka aayatan = lambaai × chaudaai × oonchaai. Patthar ke liye visthaapan vidhi lagao. Padho dravyamaan aur aayatan kaise naapein.
Taapmaan, dabaav aur ghanatva
Garam karne par kan door-door hote hain, isliye padaarth usi dravyamaan ke saath zyada jagah gherta hai aur uska ghanatva ghatta hai. Isiliye garam hawa thandi hawa ke upar uthti hai aur hot air balloon udta hai. Dabaav gaison ko chhote aayatan mein dabaakar unka ghanatva badhaata hai, par drav aur thos par lagbhag asar nahi karta. Paani alag hai: 4 °C par sabse ghana hota hai aur jamne par failta hai, isliye barf tairti hai aur neeche ke paani aur machhliyon ko bachaati hai. Prithvi ke andar parten halki crust se inner core tak ghani hoti jaati hain.
Aage badhne se pehle
Steel ke jahaazon se bahut pehle log khokhle baans aur lakdi ke latthon ke bede par nadiyaan paar karte the, jo aasaani se tairte hain. Manipur ke Ningel gaon mein parivaar aaj bhi kuon ka khaara paani dhaatu ke bartanon mein tab tak ubaalte hain jab tak namak ke crystal na ban jaayein, phir unse namak ke cake banaate hain. Har sawaal ka jawaab Chapter 9 ke NCERT solutions mein hai.
Key terms (zaroori shabd)
| Term | Matlab |
|---|---|
| Vilayan (solution) | Uniform mishran jismein ek padaarth doosre mein barabar faila ho, jaise paani mein namak ya cheeni. |
| Vilay (solute) | Jo padaarth ghulta hai; thos aur drav ke vilayan mein hamesha thos, aur do drav mein jo kam maatra mein ho. |
| Vilaayak (solvent) | Jis padaarth mein vilay ghulta hai, jaise cheeni ke ghol mein paani; do drav mein jo zyada maatra mein ho. |
| Non-uniform mishran | Aisa mishran jiske hisse barabar na faile hon aur dikhen, jaise paani mein chalk, ret ya buraada. |
| Asantript vilayan (unsaturated) | Aisa vilayan jo us taapmaan par aur vilay ghol sakta hai. |
| Santript vilayan (saturated) | Aisa vilayan jo us taapmaan par aur vilay nahi ghol sakta; faaltu vilay neeche baith jaata hai. |
| Saandrata (concentration) | Tay maatra ke vilayan ya vilaayak mein vilay ki maatra; tanu (dilute) mein kam vilay, saandra (concentrated) mein zyada. |
| Ghulansheelta (solubility) | Kisi taapmaan par tay maatra (100 mL) vilaayak mein ghul sakne wala sabse zyada vilay. |
| Ghanatva (density) | Kisi padaarth ke ikai aayatan ka dravyamaan: ghanatva = dravyamaan ÷ aayatan, kg/m³, g/cm³ ya g/mL mein. |
| Saapeksh ghanatva (relative density) | Kisi padaarth ka ghanatva ÷ paani ka ghanatva; bina unit ki ek sankhya. |
| Dravyamaan (mass) | Kisi cheez mein padaarth ki maatra, balance se gram ya kilogram mein naapi jaati hai. |
| Bhaar (weight) | Wo bal jisse Prithvi kisi cheez ko kheenchti hai, newton mein naapa jaata hai. |
| Meniscus | Measuring cylinder mein drav ki mudi hui sateh; paani ke liye iska nichla hissa padho, rangeen drav ke liye upari. |
| Visthaapan vidhi (displacement method) | Kisi be-dhang thos ko measuring cylinder ke paani mein utaarkar, paani ke star ki badhat se uska aayatan nikaalna. |
Is chapter ke topics
Practice karo
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Inmein se vilayan kaun sa hai?
Jawab dekho
Jawab: (c) Paani mein ghuli cheeni
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Chashni (cheeni ki chaasni) mein vilaayak kya hai?
Jawab dekho
Jawab: (b) paani
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Paani ka taapmaan badhne par usmein oxygen ki ghulansheelta:
Jawab dekho
Jawab: (b) ghatti hai
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Ghanatva ki SI unit hai:
Jawab dekho
Jawab: (b) kg/m³
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100 mL ke measuring cylinder mein 10 mL aur 20 mL ke nishaanon ke beech 10 chhote bhaag hain. Iski sabse chhoti reading hai:
Jawab dekho
Jawab: (b) 1 mL
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Paani sabse ghana kis taapmaan par hota hai?
Jawab dekho
Jawab: (b) 4 °C
Students ke sawal
Class 8 Science Chapter 9 ke mukhya topics kya hain?
Vilayan aur uske hisse, vilay aur vilaayak; uniform aur non-uniform mishran; santript aur asantript vilayan, saandrata aur ghulansheelta; taapmaan thos aur gaison ki ghulansheelta ko kaise badalta hai; ghanatva aur saapeksh ghanatva; digital balance se dravyamaan aur measuring cylinder se aayatan naapna; aur taapmaan aur dabaav ghanatva ko kaise badalte hain.
Kya The Amazing World of Solutes, Solvents, and Solutions naye NCERT Class 8 Science book mein hai?
Haan. Ye Curiosity, Class 8 Science textbook (Reprint 2026-27) ka Chapter 9 hai, pages 134 se 151 tak. Ye Nature of Matter: Elements, Compounds, and Mixtures ke baad aata hai, jisne uniform mishran se parichay karaaya tha.
Santript aur asantript vilayan mein kya antar hai?
Asantript vilayan us taapmaan par aur vilay ghol sakta hai. Santript vilayan jitna ghol sakta tha, ghol chuka hai, isliye aur daala gaya vilay neeche baith jaata hai. Thos vilay ke santript vilayan ko garam karne par wo aksar phir asantript ho jaata hai, kyunki ab aur ghul sakta hai.
Tel paani par kyon tairta hai?
Tel paani se kam ghana hai. 1 litre tel ke pack ka dravyamaan sirf lagbhag 910 g hota hai, jabki 1 litre paani lagbhag 1000 g ka hota hai. Isliye tel ka ghanatva lagbhag 0.91 g/mL hai, paani ke 1 g/mL se kam, aur wo upar rehta hai.
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