Answer
Verified
396.6k+ views
Hint: Hard water has salts of the elements which belong to the s-block, especially group 2 elements. When the soap and the salts combine a precipitate is formed rather than mixing up.
Complete step by step answer:
Natural water contains dissolved salts. Depending on the behavior towards soap solution water is classified as soft and hard water:
Soft water: Water that produces lather with soap readily is called soft water. Examples of soft water are rainwater, distilled water, and demineralized water.
Hard water: Water that does not form lather easily with water is called hard water. Some examples of hard water are river water, seawater, spring water, etc.
Cause of hardness of water: It has been established that hardness of water is due to the presence of bicarbonates, chlorides, and sulphonates of magnesium and calcium in it. Hard water does not form lather easily with soap or soap does not work in hard water. This is because:
Soap is sodium or potassium salt of certain higher fatty acids such as stearic acid, palmitic acid, etc. When hard water is treated with soap solution, \[C{{a}^{2+}}\] and \[M{{g}^{2+}}\] ions present in hard water react with the anions of fatty acids present in soap to form scum or curdy white precipitates. As a result, hard water does not produce lather with soap immediately.
\[2{{C}_{17}}{{H}_{35}}CO{{O}^{-}}N{{a}^{+}}+CaC{{l}_{2}}\to {{({{C}_{17}}{{H}_{35}}COO)}_{2}}Ca\downarrow +2NaCl\]
\[2{{C}_{17}}{{H}_{35}}CO{{O}^{-}}N{{a}^{+}}+MgS{{O}_{4}}\to {{({{C}_{17}}{{H}_{35}}COO)}_{2}}Mg\downarrow +N{{a}_{2}}S{{O}_{4}}\]
Thus, hard water is not suitable for washing purposes since a lot of soap is wasted in precipitating out and ions present in hard water.
Note:
However, when all the \[C{{a}^{2+}}\] and \[M{{g}^{2+}}\] ions present in hard water have been precipitated by addition of sufficient amount of soap, resulting water becomes soft and readily produce lather with soap. Instead, we can use detergent in the hard water because it forms lather with detergent.
Complete step by step answer:
Natural water contains dissolved salts. Depending on the behavior towards soap solution water is classified as soft and hard water:
Soft water: Water that produces lather with soap readily is called soft water. Examples of soft water are rainwater, distilled water, and demineralized water.
Hard water: Water that does not form lather easily with water is called hard water. Some examples of hard water are river water, seawater, spring water, etc.
Cause of hardness of water: It has been established that hardness of water is due to the presence of bicarbonates, chlorides, and sulphonates of magnesium and calcium in it. Hard water does not form lather easily with soap or soap does not work in hard water. This is because:
Soap is sodium or potassium salt of certain higher fatty acids such as stearic acid, palmitic acid, etc. When hard water is treated with soap solution, \[C{{a}^{2+}}\] and \[M{{g}^{2+}}\] ions present in hard water react with the anions of fatty acids present in soap to form scum or curdy white precipitates. As a result, hard water does not produce lather with soap immediately.
\[2{{C}_{17}}{{H}_{35}}CO{{O}^{-}}N{{a}^{+}}+CaC{{l}_{2}}\to {{({{C}_{17}}{{H}_{35}}COO)}_{2}}Ca\downarrow +2NaCl\]
\[2{{C}_{17}}{{H}_{35}}CO{{O}^{-}}N{{a}^{+}}+MgS{{O}_{4}}\to {{({{C}_{17}}{{H}_{35}}COO)}_{2}}Mg\downarrow +N{{a}_{2}}S{{O}_{4}}\]
Thus, hard water is not suitable for washing purposes since a lot of soap is wasted in precipitating out and ions present in hard water.
Note:
However, when all the \[C{{a}^{2+}}\] and \[M{{g}^{2+}}\] ions present in hard water have been precipitated by addition of sufficient amount of soap, resulting water becomes soft and readily produce lather with soap. Instead, we can use detergent in the hard water because it forms lather with detergent.
Recently Updated Pages
Basicity of sulphurous acid and sulphuric acid are
Three beakers labelled as A B and C each containing 25 mL of water were taken A small amount of NaOH anhydrous CuSO4 and NaCl were added to the beakers A B and C respectively It was observed that there was an increase in the temperature of the solutions contained in beakers A and B whereas in case of beaker C the temperature of the solution falls Which one of the following statements isarecorrect i In beakers A and B exothermic process has occurred ii In beakers A and B endothermic process has occurred iii In beaker C exothermic process has occurred iv In beaker C endothermic process has occurred
The branch of science which deals with nature and natural class 10 physics CBSE
The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths
How do you arrange NH4 + BF3 H2O C2H2 in increasing class 11 chemistry CBSE
Is H mCT and q mCT the same thing If so which is more class 11 chemistry CBSE
Trending doubts
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Write an application to the principal requesting five class 10 english CBSE
Difference Between Plant Cell and Animal Cell
a Tabulate the differences in the characteristics of class 12 chemistry CBSE
Change the following sentences into negative and interrogative class 10 english CBSE
What organs are located on the left side of your body class 11 biology CBSE
Discuss what these phrases mean to you A a yellow wood class 9 english CBSE
List some examples of Rabi and Kharif crops class 8 biology CBSE