LAQ for Chapter 2 Exploring Substances: Acidic, Basic and Neutral Class 7 Science NCERT
Important Questions1
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Acids are substances known for their sour taste (though tasting them is not safe). The word "acid" is derived from the Latin word 'ACERE', meaning sour.
Properties of Acids:
• Sour in taste.
• Turn blue litmus paper red.
• Turn China rose solution dark pink or magenta.
Examples of acidic substances include curd, vinegar, lemon, and orange juice, which all contain natural acids. 
Citrus Fruits are Acidic in Nature
2
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Bases are substances with a bitter taste and a slippery feel.
Properties of Bases:
• Bitter in taste.
• Turn red litmus paper blue.
• Turn turmeric paper reddish-brown.
• Turn China rose solution green.
Some common examples of bases include baking soda, milk of magnesia, and soap. The chemical nature of these substances is referred to as basic.
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4
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Neutralisation is a process in which an acid solution when mixed with base solution, react with each other to produce a salt and water along with generation of heat. Salt so produced, may be acidic, basic or neutral in nature. In this process the acidic nature of the acid and the basic nature of the base are destroyed.
NeutralizationAcid + base → salt + water. (heat is evolved)
For example: HCl + NaOH→ NaCl + H2O.
Hydrochloric acid + Sodiumhydroxide → Sodium chloride + Water
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When an ant bites, it injects an acidic liquid called formic acid into the skin, causing burning pain, redness, and irritation. The effect of the acid can be neutralized by applying a mild base to the affected area.
Two common treatments are:
1. Baking soda solution: Baking soda (sodium hydrogen carbonate) neutralizes the acid and reduces the pain and irritation.
2. Calamine solution: Calamine contains zinc carbonate, which also neutralizes the acidic effect and provides relief.
Applying either of these substances helps neutralize the acid and reduce the discomfort caused by the ant bite.