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प्रश्न
Explain why an aqueous solution of sodium chloride is neutral but an aqueous solution of sodium carbonate is basic (or alkaline). Write chemical equations of the reactions involved.
उत्तर
NaCl(s) + H2O(l) → NaOH(aq) + HCl(aq)
An aqueous solution of sodium carbonate (washing soda) is alkaline because it is a salt prepared from the reaction of a weak acid, carbonic acid (H2CO3), and a strong base, sodium hydroxide (NaOH). When sodium carbonate is dissolved in water, it gets hydrolysed to some extent and forms sodium hydroxide and carbonic acid.
Na2CO3(s) + 2H2O(l) → 2NaOH(aq) + H2CO3(aq)
Sodium hydroxide, being a strong base, is fully ionised to give a large amount of hydroxide ions (OH-), and carbonic acid, being a weak acid, is slightly ionised to form a small amount of hydrogen (H+) ions. Therefore, an aqueous solution contains more hydroxide ions than hydrogen ions, and this makes the solution basic.
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संबंधित प्रश्न
Name a metal carbonate which is soluble in water.
Fill in the following blank:
Sodium hydrogen carbonate is .................. soda whereas sodium carbonate is ................. soda.
What is washing soda?
Write the formulae of sodium chloride and sodium carbonate.
Describe how washing soda is produced starting from sodium chloride (common salt). Write equations of all the reactions involved.
State whether an aqueous solution of washing soda is acidic or alkaline? Give reason for your answer.
What is meant by saying that washing soda has detergent properties?
Answer the following question.
How is washing soda prepared from sodium carbonate? Give its chemical equation. State the type of this salt. Name the type of hardness of water that can be removed by it?
Chemical formula of washing soda is ____________.
Correct the wrong statement given below:
Magnesium hydroxide is used in whitewashing buildings.
