← Unit 5: Electricity and Acids, Bases and Salts Integrated Science · Grade 9 ← Prev25 / 43Next →
Communication and Collaboration

Listen: Acids, Bases and Salts

Listen: Acids, Bases and Salts

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Transcript

[0:00] Acids are substances that taste sour and turn blue litmus paper red. Lemon juice and vinegar are common examples. [0:45] Bases feel slippery and turn red litmus paper blue. Soluble bases are called alkalis, like the sodium hydroxide in some soaps. [1:35] The pH scale runs from 0 to 14. A pH below 7 is acidic, exactly 7 is neutral, and above 7 is basic or alkaline. [2:25] Indicators such as litmus or universal indicator change colour to show how acidic or basic a solution is. [3:15] When an acid reacts with a base, they cancel each other out in a reaction called neutralisation, forming a salt and water.

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