Acids, bases & salts
Base — ক্ষারক
Quick answer
A substance that gives OH⁻ ions in water or accepts H⁺; bases feel soapy, turn red litmus blue and have pH above 7.
Definition
A base is a substance that releases hydroxide ions, OH⁻, in water, or accepts H⁺ ions from an acid. Bases feel soapy, taste bitter, turn red litmus blue and sit above pH 7. Water-soluble bases such as sodium hydroxide () are called alkalis; insoluble ones like copper(II) hydroxide do not dissolve, so they are not alkalis. Strength depends on dissociation: strong bases release OH⁻ fully, weak bases like ammonia only partly.
For example
The white chuna (slaked lime) brushed on a paan leaf is a mild base; soap and detergent solutions are also basic, which is why they feel slippery.