Class 7 Science Chapter 2: Exploring Substances: Acidic, Basic, and Neutral (Hinglish Notes)

Ye chapter kis baare mein hai?

Chapter 28 February, National Science Day, pe ek school ke science mele se shuru hota hai. Aane waalon ko saade safed kaagaz diye jaate hain, aur jaise hi un pe spray hota hai, science ki adbhut duniya mein swaagat ka sandesh ubhar aata hai. Kaise? Jawab ek saral vichaar mein hai: kai padaarth acidic, basic ya neutral hote hain, aur kuch padaarth, jinhe indicator kehte hain, rang badalkar ye batate hain.

Litmus se jaanch

Litmus lichens se milne waala prakritik rang hai, jo neele aur laal kaagaz ke roop mein milta hai. Har namoone ki ek boond dono pe daalo. Sirka, nimbu ka ras, imli ka paani aur amla ka ras neeli litmus ko laal karte hain: ye acidic hain. Baking soda ka ghol, saabun ka ghol, washing powder ka ghol aur choone ka paani laal litmus ko neela karte hain: ye basic hain. Nal ka paani, cheeni ka ghol aur namak ka ghol dono kaagaz waise hi chhod dete hain: ye neutral hain. Litmus acid aur base mein alag rang leta hai, isliye ye acid-base indicator hai.

Khatta aur kadva

Acidic samooh ke jo namoone khaaye jaate hain, sab khatte hain, kyunki unme acid hain: santare mein citric acid, amla mein ascorbic acid (vitamin C) aur citric acid, kachche aam aur imli mein tartaric acid, aur tamatar mein citric aur oxalic acid. Base aam taur pe kadve aur chikne hote hain, jaise ungliyon ke beech baking soda ka ghol. Par kadva hamesha basic nahi hota: karela kadva hai, phir bhi base nahi. Aur kisi anjaan padaarth ko kabhi mat chakho. Aur padho acids, bases aur indicators mein.

Prakriti ke indicators

Litmus akela indicator nahi hai. Kuchle hue pankhudiyon ko garam paani mein bhigokar aur chhaankar bana red rose extract acid mein laal aur base mein hara ho jaata hai. Haldi ka kaagaz base mein laal ho jaata hai par acid aur neutral padaarthon mein peela rehta hai, isliye ye base pakad sakta hai par acid ko neutral se alag nahi kar sakta. Isiliye peele sabzi ke daag pe saabun lagaane se wo laal ho jaata hai. Chukandar, baingani patta gobhi, jamun aur laal gudhal se bhi indicator bante hain, aur hydrangea ke paudhe acidic mitti mein neele aur basic mitti mein gulaabi ya laal phool dete hain. Kuch indicator gandh se kaam karte hain: kati pyaaz ke saath rakhi pattiyon ki pyaaz waali gandh base mein ud jaati hai. Dekho natural indicators kaise banayein.

Neutralisation

Activity 2.7 mein paani mein nimbu ke ras ki ek boond neele litmus ghol se laal ho jaati hai. Jab choone ka paani boond boond daalte hain, rang laal se neela ho jaata hai: ghol ab acidic nahi raha, kyunki base ne acid ko khatm kar diya. Ise neutralisation kehte hain. Jab acid aur base sahi maatra mein kriya karte hain, nateeja na acidic hota hai na basic, aur namak, paani aur garmi bante hain:

Acid + Base → Namak (salt) + Paani + Garmi

Roz ki zindagi mein neutralisation

Yahi kriya roz ki mushkilein hal karti hai. Laal cheenti ke kaatne pe formic acid jaata hai, isliye geela baking soda, jo base hai, ragadne se jalan kam hoti hai. Zyaada chemical khaad mitti ko acidic bana sakti hai; kisaan choona, ek base, daalte hain. Basic mitti mein khaad ya compost daalte hain, jinke organic padaarth acid chhodte hain. Aur factory ke acidic kachre ko jheel tak pahunchne se pehle base se neutral karna chahiye, taaki machhliyan bachein. Padho neutralisation kya hai.

Paheli hal, aur ek mahaan chemist

Mele ka swaagat sandesh shaayad saabun ke ghol se likha gaya tha, jo basic hai, aur phir us pe haldi ka ghol spray kiya gaya: kaagaz peela ho jaata hai aur chhupe akshar laal ho jaate hain. Chapter Acharya Prafulla Chandra Ray se bhi milwaata hai, Modern Indian Chemistry ke pita, jinhone 1901 mein India ki pehli dawa company shuru ki aur pracheen Bharat ki chemistry ke baare mein likha.

Har activity ke sawaal aur saare baarah exercise sawaalon ke jawab, Dive Deeper paheli ke saath, Chapter 2 ke NCERT solutions mein hain.