Litmus ek Indicator

Class 7 Science · Chapter 2: Padaarthon ki Khoj: Acidic, Basic aur Neutral · NCERT Curiosity section 2.1–2.1.1

Seekho

Science mele mein Meher aur Kabir ko khaali safed kaagaz diye jaate hain. Ek sevak un par koi tarl chhidakta hai, aur shabd "Welcome to the Wonderful World of Science" ubhar aate hain! "Padaarthon ki rangeen duniya" stall par ve jaanne ka faisla karte hain ki kaise. Pata chalta hai, prakriti hamari science prayogshaala hai.

Ve neembu ras, saabun ka ghol, sirka, baking soda ghol, choone ka paani, cheeni aur namak ke gholon ki boondein neele aur laal litmus kaagaz ke tukdon par daalte hain. Kuch namoone neele litmus ko laal karte hain, kuch laal litmus ko neela, aur kuch kisi ko nahi badalte.

Jo neele litmus ko laal karein ve acidic; jo laal ko neela karein ve basic; jo kisi ko na badlein ve neutral. Litmus lichen (saath rehte ek fungus aur ek alga) se milta hai. Acid aur base mein alag rang dikhaane ke kaaran ye acid-base indicator hai.

blue → red: acidic · red → blue: basic · no change: neutral

Acidic khaane khatte hote hain: neembu aur santre mein citric acid, aamle mein ascorbic acid (vitamin C), imli mein tartaric acid, dahi mein lactic acid aur sirke mein acetic acid. Base saabun jaise chikne lagte hain aur aksar kadve, par har kadvi cheez (jaise karela) basic nahi. Anjaan cheez kabhi mat chakho!

Explore: litmus test.

1. Har namoona litmus se test karke sort karo.

Yaad rakho

• Acid neele litmus ko laal; base laal ko neela; neutral kisi ko nahi.
• Lichen se bana litmus ek acid-base indicator hai.

Quick check

Ek tarl laal litmus ko neela karta hai. Uski prakriti?

1. basic
2. acidic
3. neutral
4. it cannot be told

Socho

Baarish, nadi aur nal ka paani: kaise pata karoge ki har ek acidic, basic ya neutral hai?

Practice

Teen levels (easy, medium, hard) ke naye sawaalon se practice karo, kuch hands-on, hints aur hal ke saath. Topic poora karne ke liye pichhle 5 mein se 4 sahi karo.