When sodium carbonate crystals are heated, their hydrated nature decreases. This is related to which idea?
Answer and explanation
Correct answer: Water of crystallisation
The governing concept is water of crystallisation, the definite number of water molecules chemically associated with some salt crystals. Washing soda is commonly represented as Na2CO3·10H2O. On heating, some or all of this crystallisation water can be removed, changing the hydrated salt into a less hydrated or anhydrous form. Heat of neutralisation, litmus change, and metal displacement describe different processes. Hence option A is correct.
Frequently asked questions
What is the correct answer to this question?
Water of crystallisation
Why is this the correct answer?
The governing concept is water of crystallisation, the definite number of water molecules chemically associated with some salt crystals. Washing soda is commonly represented as Na2CO3·10H2O. On heating, some or all of this crystallisation water can be removed, changing the hydrated salt into a less hydrated or anhydrous form. Heat of neutralisation, litmus change, and metal displacement describe different processes. Hence option A is correct.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
