Combustion kya hai?

Combustion kya hai?

Metals aur non-metals waale chapter mein magnesium ribbon jalaana yaad karo. Ribbon chakaachaundh roshni ke saath jalta hai aur safed powder, magnesium oxide, chhodta hai. Naya padaarth bana, isliye ye chemical change hai, aur saath mein garmi aur roshni bhi nikalti hai. Chhote mein: magnesium + oxygen → magnesium oxide + garmi + roshni. Jab koi padaarth oxygen ke saath reaction karke garmi aur/ya roshni de, to us reaction ko combustion kehte hain. Lakdi, kaagaz, cotton aur kerosene is tarah jal sakte hain, isliye ye combustible padaarth hain.

Jalne ko oxygen chahiye

Activity 5.5 jaanchti hai ki kya hawa zaroori hai. Do ek jaisi mombattiyan petri dish pe jalao aur ek ko glass ke tumbler se dhak do. Khuli mombatti jalti rehti hai, par dhaki hui kuch der baad bujh jaati hai, kyunki use taazi hawa nahi milti. Hawa ka jo hissa jalne mein madad karta hai, vo oxygen hai. Pakka karne ke liye tumbler ke neeche ki dish mein thoda lime water daalo: vo doodhiya ho jaata hai, yaani carbon dioxide bani. Ye carbon dioxide wax ke carbon aur hawa ki oxygen se bani, jo dikhata hai ki combustion oxygen leta hai.

Aag se suraksha

Agar kisi ke kapdon mein aag lag jaaye, to turant us insaan ke chaaron or kambal ya mota kapda lapet do. Taazi hawa na milne se aag bujh jaati hai. Synthetic kambal ya kapda kabhi use mat karo, kyunki vo pighalkar twacha se chipak sakta hai.

Bina garmi ki roshni

Garmiyon ki shaam ko baag ya khet mein jugnu chamakte dikh sakte hain. Unki roshni bhi chemical change se aati hai, par lau ke ulat isme garmi nahi hoti. Jeevit cheezon ki is tarah bani roshni ko bioluminescence kehte hain.

Ignition temperature

Kaagaz aasaani se jalta hai, phir bhi ek panna saalon khuli hawa mein pada rahe aur kabhi aag na pakde. Aur kya chahiye? Activity 5.6 mein, jo teacher ya kisi bade ki maujoodgi mein karni hai, chimte mein pakde kaagaz ke paas jalti maachis laayi jaati hai, aur kaagaz jaldi aag pakad leta hai. Ab doosre kaagaz pe magnifying glass se dhoop ikatthi karke sabse chhota, sabse chamakdaar dhabba banao aur wahin rakho. Kaagaz pehle dhuaan deta hai aur phir bina kisi lau ke jal uthta hai. Ikatthi dhoop kaagaz ko garam karti hai, uska taapmaan badhta jaata hai, aur aakhir vo jalne laayak garam ho jaata hai. Jis sabse kam taapmaan par koi padaarth aag pakade, vo uska ignition temperature hai. Maachis ki lau pehle se usse zyaada garam thi, isliye kaagaz lagbhag turant jal gaya.

Fire triangle

To combustion ko teen cheezein chahiye, jinhe fire triangle se dikhaate hain: combustible padaarth, jise fuel bhi kehte hain; oxygen; aur itni garmi jo fuel ko ignition temperature tak pahunchaaye. Koi bhi ek bhuja hatao to aag jaari nahi reh sakti, isiliye hawa rokne waala kambal jalte kapdon ki aag bujha deta hai.

Jalti mombatti kya dikhaati hai

Mombatti jalti hai to lau ki garmi wax ko pighaalti hai, pighla wax batti pe chadhkar vaashp banta hai, aur neeche tapakta pighla wax phir jam jaata hai: ye sab physical changes hain. Phir wax ki vaashp jalkar lau banaati hai, jo chemical change hai. Isliye jalti mombatti mein physical aur chemical dono badlaav saath-saath hote hain. Unnisvi sadi mein scientist Michael Faraday ne The Chemical History of a Candle naam se lectures diye, jinme mombatti se pighalna, vaashp banna aur combustion samjhaaya.

Ye kyun zaroori hai

Combustion samajhne se hum fuel ka sahi upyog kar sakte hain aur aag surakshit tareeke se bujha sakte hain. Chemical changes physical se kaise alag hain, ye physical aur chemical changes mein hai, aur kaunse badlaav ulte ho sakte hain, ye reversible aur irreversible changes kya hain mein. Har activity aur sawaal ke jawaab Chapter 5 ke NCERT solutions mein hain; poore Chapter 5 ke notes bhi dekho.