Describe methods to remove the temporary hardness of water: $(i)$ Boiling $(ii)$ Clark's method.
(N/A) $(i)$ Boiling: During boiling,the soluble $Mg(HCO_{3})_{2}$ is converted into insoluble $Mg(OH)_{2}$ and $Ca(HCO_{3})_{2}$ is changed to insoluble $CaCO_{3}$. Because the solubility product of $Mg(OH)_{2}$ is lower than that of $MgCO_{3}$,$Mg(OH)_{2}$ precipitates out. These precipitates can be removed by filtration to obtain soft water.
$Mg(HCO_{3})_{2} \xrightarrow{\Delta} Mg(OH)_{2} \downarrow + 2CO_{2} \uparrow$
$Ca(HCO_{3})_{2} \xrightarrow{\Delta} CaCO_{3} \downarrow + H_{2}O + CO_{2} \uparrow$
$(ii)$ Clark's method: In this method,a calculated amount of lime $(Ca(OH)_{2})$ is added to hard water. It precipitates calcium carbonate and magnesium hydroxide,which can be filtered off.
$Ca(HCO_{3})_{2} + Ca(OH)_{2} \longrightarrow 2CaCO_{3} \downarrow + 2H_{2}O$
$Mg(HCO_{3})_{2} + 2Ca(OH)_{2} \longrightarrow 2CaCO_{3} \downarrow + Mg(OH)_{2} \downarrow + 2H_{2}O$
$Mg(HCO_{3})_{2} \xrightarrow{\Delta} Mg(OH)_{2} \downarrow + 2CO_{2} \uparrow$
$Ca(HCO_{3})_{2} \xrightarrow{\Delta} CaCO_{3} \downarrow + H_{2}O + CO_{2} \uparrow$
$(ii)$ Clark's method: In this method,a calculated amount of lime $(Ca(OH)_{2})$ is added to hard water. It precipitates calcium carbonate and magnesium hydroxide,which can be filtered off.
$Ca(HCO_{3})_{2} + Ca(OH)_{2} \longrightarrow 2CaCO_{3} \downarrow + 2H_{2}O$
$Mg(HCO_{3})_{2} + 2Ca(OH)_{2} \longrightarrow 2CaCO_{3} \downarrow + Mg(OH)_{2} \downarrow + 2H_{2}O$
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Similar Questions
Identify the statements which are not correct from the following:
a) In the structure of ice,each oxygen atom is surrounded by $4$ other hydrogen atoms via hydrogen bonding.
b) Temporary hardness of water is due to dissolved $Mg(HCO_3)_2$ and $Ca(HCO_3)_2$,not $NaHCO_3$.
c) In the reaction of acidified $KMnO_4$ and $H_2O_2$,$H_2O_2$ acts as a reducing agent.
d) $3 \ g \ L^{-1}$ $H_2O_2$ is not equal to $100$ volume $H_2O_2$ (since $100$ volume $H_2O_2$ is approximately $303.7 \ g \ L^{-1}$).
a) In the structure of ice,each oxygen atom is surrounded by $4$ other hydrogen atoms via hydrogen bonding.
b) Temporary hardness of water is due to dissolved $Mg(HCO_3)_2$ and $Ca(HCO_3)_2$,not $NaHCO_3$.
c) In the reaction of acidified $KMnO_4$ and $H_2O_2$,$H_2O_2$ acts as a reducing agent.
d) $3 \ g \ L^{-1}$ $H_2O_2$ is not equal to $100$ volume $H_2O_2$ (since $100$ volume $H_2O_2$ is approximately $303.7 \ g \ L^{-1}$).
Which of the following statements is not correct?
Easy
View SolutionHow many hydrogen-bonded water molecule$(s)$ are associated in $CuSO_{4} \cdot 5H_{2}O$?
Easy
View SolutionMatch the following methods for treating hardness of water with their corresponding reagents used.
List-$I$ List-$II$ $A$. Treatment with washing soda $I$. $Ca(OH)_2$ $B$. Calgon's method $II$. $Na_2CO_3$ $C$. Clark's method $III$. $NaAlSiO_4$ $D$. Zeolite/permutit process $IV$. $Na_6P_6O_{18}$
The correct match is:
| List-$I$ | List-$II$ |
|---|---|
| $A$. Treatment with washing soda | $I$. $Ca(OH)_2$ |
| $B$. Calgon's method | $II$. $Na_2CO_3$ |
| $C$. Clark's method | $III$. $NaAlSiO_4$ |
| $D$. Zeolite/permutit process | $IV$. $Na_6P_6O_{18}$ |
The correct match is:
Describe the methods to remove the permanent hardness of water.
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