Advertisements
Advertisements
Question
Explain by writing a word equation.
Hard water gets softened on mixing with a solution of washing soda.
Advertisements
Solution
To soften the hard water, a solution of washing soda is added to it. This results in a chemical reaction to form a precipitate of insoluble carbonate salts of calcium and magnesium. As the dissolved salts of calcium and magnesium go out in the form of a precipitate of the carbonate salts, the water is softened. The following equation can be written for this chemical change.
Word equation:
Calcium chloride + Sodium carbonate `→` Calcium carbonate + Sodium chloride
Chemical equation (unbalanced):
CaCl2 + Na2CO3 → CaCO3 + NaCl
RELATED QUESTIONS
TRUE \ FALSE
Evaporation of water is a physical change. True or false ?
Name the type of chemical reaction shown by the following equation:
NaOH + HCl → NaCl + H2O
Choose the correct option from the bracket and explain the statement giving reason.
(Oxidation, displacement, electrolysis, reduction, zinc, copper, double displacement, decomposition)
To prevent rusting, a layer of ______ metal is applied on iron sheets.
When electric current is passed through acidulated water ______ of water takes place.
What do you understand by precipitation reaction? Explain with examples.
Multiple choice:
Which of the following is not a characteristic of a chemical change?
What do you observe when Cl2 is passed through potassium iodide (KI) solution.
A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about an hour.
Write a word equation for the chemical change, if any.
Heat may evolve or be absorbed during a ______ change.
Write a note on the catalyst.
