Metals Ki Dheemi Maut 🛡️
Chapter ka aakhri hissa. Metals hawa, nami aur gases ke sampark mein aakar dheere-dheere kharab hoti rehti hain — isse corrosion (ksharan) kehte hain. Ye ek oxidation (oxeekaran) reaction (abhikriya) hai.
| Metal (dhaatu) | Kya banta hai | Dikhta kaisa hai |
|---|---|---|
| Loha (Fe) | Hydrated iron oxide (zang/rust) | Bhoori-laal, bhurbhuri parat |
| Chandi (Ag) | Silver sulphide (Ag₂S) | Kaali parat |
| Tamba (Cu) | Basic copper carbonate | Hari parat |
| Aluminium (Al) | Al₂O₃ | Safed — par ye bachati hai! |
⚠️ Zang aur Al₂O₃ mein bada farak: Zang bhurbhura hota hai aur jhad jaata hai — jisse andar ka naya loha phir hawa ke sampark mein aata hai aur zang badhta rehta hai, jab tak poora loha khatm na ho jaaye. Par aluminium ki oxide parat chipki hui aur majboot hoti hai — wo andar ki metal ko bacha leti hai. Isiliye loha sadta hai, aluminium nahi.
💧 Zang Lagne Ke Liye Kya Chahiye?
📌 Zang lagne ke liye DONO zaroori hain:
1️⃣ Oxygen (hawa) aur 2️⃣ Paani / nami
In dono mein se koi ek bhi hata do, toh zang ruk jaata hai. Sara
bachav isi ek baat par tika hai!
Tateey (coastal) ilaakon mein gaadiyan aur pul zyada jaldi zang pakadte hain, kyunki hawa mein namak (salt) aur nami dono zyada hoti hai — aur namak wala paani bijli achhi conduct karta hai, jisse corrosion ki electrochemical reaction tez ho jaati hai. Isiliye Mumbai aur Chennai mein gaadiyon ko zyada dekhbhaal chahiye hoti hai!
🛡️ Zang Se Bachne Ke Tareeke
| Tareeka | Kaise kaam karta hai | Kahan use hota hai |
|---|---|---|
| Painting | Hawa-paani se parat bana deta hai | Grill, gate, pul, gaadi |
| Oiling / greasing | Chikni parat nami rokti hai | Machine ke parts, auzaar |
| Galvanisation | Lohe par zinc ki parat chadhana | Chhat ki chaadar, keel, pipe |
| Electroplating | Bijli se doosri metal ki parat chadhana | Gehne, nal, bartan |
| Alloying | Dusri metal milakar zang-rodhi banana | Stainless steel |
💡 Galvanisation itna khaas kyun hai? Zinc, lohe se zyada reactive hai — isliye wo pehle khud react karta hai aur lohe ko bachaata hai. Aur mazedaar baat: agar parat kahin se khiskh bhi jaaye, tab bhi zinc lohe ko bachata rehta hai! Isiliye ise "sacrificial protection" (balidaan wali suraksha) kehte hain.
⚗️ Alloys — Metals Ka Mishran
📌 Alloy (mishradhatu): Do ya zyada metals ka (ya metal + non-metal ka) samaangi mishran. Alloy banane se metal zyada majboot, zang-rodhi aur upyogi ho jaati hai.
| Alloy | Kis se bana | Kahan use hota hai |
|---|---|---|
| Stainless steel | Fe + Cr + Ni (+C) | Bartan, chhuri, aujaar — zang nahi lagta |
| Brass (pital) | Cu + Zn | Bartan, murti, taale |
| Bronze (kaansa) | Cu + Sn | Murtiyan, ghanti, medal |
| Solder | Pb + Sn | Bijli ke taar jodna (kam M.P.) |
| Amalgam | Koi metal + mercury | Daanton ki filling |
Shuddh sona (24 carat) itna naram hota hai ki usse gehne ban hi nahi sakte — wo mud jaayenge! Isliye usme thoda tamba ya chandi milaya jaata hai, jisse 22 carat sona banta hai (22 bhaag sona + 2 bhaag doosri metal). Ye kada hota hai aur gehne banane layak. Toh agli baar jab koi "22 carat" kahe — aapko pata hai wo ek alloy ki baat kar raha hai!
📖 Chapter Summary
✅ Metals: chamak, malleable, ductile, conductor, sonorous | Non-metals: brittle, dull, insulator
✅ Apwaad: Hg (drav metal), Br (drav non-metal), graphite (conductor non-metal), Na-K (naram)
✅ Reactivity series: K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au
✅ Ionic bond = electron ka poora transfer; lattice; pighle par bijli conduct
✅ Metallurgy: concentration → roasting/calcination → reduction (apchayan) → refining
✅ Corrosion ke liye oxygen + paani dono chahiye; bachav: paint, grease, galvanisation, alloy
🧠 Apne Aap Ko Test Karo
🧊 Poore chapter ka nichod — 3D mein ionic bond aur crystal lattice khud explore karo!
Open 3D Ionic Bond Lab →