Chapter 02 Acids, Bases and Salts Questions-05
QUESTIONS
1. What is the common name of the compound $CaOCl_2$ ?
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Answer
The common name of the compound $CaOCl_2$ is bleaching powder.
2. Name the substance which on treatment with chlorine yields bleaching powder.
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Answer
Calcium hydroxide $ [Ca (OH) _2]$, on treatment with chlorine, yields bleaching powder.
3. Name the sodium compound which is used for softening hard water.
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Answer
Washing soda $(Na_2CO_3 \cdot 10H_2O) $ is used for softening hard water.
4. What will happen if a solution of sodium hydrocarbonate is heated? Give the equation of the reaction involved.
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Answer
When a solution of sodium hydrocarbonate (sodium hydrogencarbonate) is heated, sodium carbonate and water are formed with the evolution of carbon dioxide gas.
$\underset{\text{Sodium hydrogencarbonate}}{2NaHCO_3} \xrightarrow{\Delta} \underset{\text{Sodium carbonate}}{Na_2CO_3} + \underset{\text{Water}}{H_2O} + \underset{\text{Carbon dioxide}}{CO_2}$
5. Write an equation to show the reaction between Plaster of Paris and water.
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Answer
The chemical equation for the reaction of Plaster of Paris and water can be represented as
$\underset{\text{Plaster of Paris}}{CaSO_4 \cdot \dfrac{1}{2} H_2 O}+ \underset{\text{Water}}{1 \dfrac{1}{2} H_2 O} \longrightarrow \underset{\text{Gypsum}}{CaSO_4 \cdot 2 H_2 O}$
