ChemistryKhaga · Class 6-8
Jang: loha ka chupchaap chemical badlav
Baahar rakhi loha ki balti kuch hafte baad bhurbhuri aur laal-bhoori kyun ho jaati hai? Kya yeh sirf 'gandagi' hai?
Socho pehle… phir dekho jawab
Nahi, yeh ek chemical badlav hai. Loha oxygen aur paani se milkar ek naya padarth, jang (hydrated iron oxide), banata hai jo loha jaisa nahi hota. Naya padarth ban gaya, isliye jang wapas loha nahi ban sakti.
Karan ko apne dada ki purani saikil mili jiski chain par jang thi. Usne bade ki madad se khurdure kapde se jang ragdi, phir chain par thoda tel lagaya aur saikil chhat ke neeche rakhi. Hafte bhar baad bhi chain chamak rahi thi.
Chemistry: loha + oxygen + paani → jang (hydrated iron oxide). Teeno ki zaroorat hai. Sookhi hawa mein paani nahi, aur ubale hue paani par tel ki parat ho toh oxygen nahi pahunchti, isliye dono mein jang bahut dheere lagti hai. Namak ya acid jang ko tez karte hain. Jang bhurbhuri hoti hai, jhad jaati hai, aur neeche ka naya loha phir khul jaata hai.
Bachav ke tareeke: rang, tel ya grease (loha ko hawa-paani se alag karte hain); galvanising (loha par zinc ki parat); alloy jaise stainless steel (loha mein chromium milaya jaata hai).
Ghar pe try karo
Bade ki madad se teen katori lo, har ek mein ek purani loha ki keel (keel bade hi rakhein): (1) sookhi, (2) saade paani mein, (3) ubale hue thande paani mein jiske upar tel ki parat ho. Roz 5 din note karo. Ubla paani bade hi sambhaalein. Dekhne ke baad haath dho lo.
Wow!
Delhi ke Mehrauli ka Lohe ka Stambh lagbhag 1,600 saal purana maana jaata hai, aur usper aaj bhi bahut kam jang dikhti hai!
3 sawaal
- Jang lagna kaisa badlav hai?
Jawab dekho
Chemical badlav, jisme naya padarth banta hai. Loha oxygen aur paani se milkar jang naam ka naya padarth banata hai, isliye yeh chemical badlav hai.
- Jang banne ke liye loha ko kya chahiye?
Jawab dekho
Oxygen aur paani dono. Jang ke liye oxygen aur paani (nami) dono zaroori hain.
- Kaun sa tareeka loha ko jang se bachata hai?
Jawab dekho
Us par rang ya tel lagana. Rang ya tel loha ko hawa aur paani se alag rakhte hain.
NCERT se jodo: NCERT Class 7 Science — physical aur chemical badlav (jang lagna)