
The temporary hardness of water is due to _________ salts of calcium and magnesium.
A. carbonates and hydrogen carbonates
B. bicarbonates only
C. chlorides and bicarbonates
D. chlorides and sulphates
Answer
439.7k+ views
1 likes
Hint: Hard water contains minerals due to presence of salts. The temporary hard water contains insoluble salts of calcium and magnesium . These salts give calcium and magnesium cations , which makes the water hard.
Complete step by step answer:
Let us first discuss hard water first.
Hard water is a type of water in which mineral content is high. Hard water is formed when water percolates via the deposits of limestone, gypsum or chalk. It is made up of calcium and magnesium bicarbonates and sulphates.
There are two types of hardness in water, one is temporary hardness and other is permanent hardness.
(1) Temporary hardness: Temporary hardness is caused by the presence of dissolved bicarbonate salts like calcium bicarbonate and magnesium bicarbonate. These salts give calcium and magnesium cations and the bicarbonate and carbonate anions . The presence of these metal cations makes the water hard.
(2) Permanent hardness: It is usually caused by the presence of calcium chloride and calcium sulphate and magnesium chloride and magnesium sulphate in the water, which do not gets precipitated, as the temperature increases.
The temporary hardness of water is due to bicarbonates only salts of calcium and magnesium.
So, the correct answer is “Option B”.
Additional Information:
There are many ways by which temporary hardness can be removed-
(1) Boiling: After filtration, the insoluble carbonates are obtained by boiling. The reaction is
and .
(2) Clark’s process: Dissolved carbon dioxide is changed into bicarbonates and then carbonates . As a result, solubility products of salt are increased which causes calcium carbonate to precipitate. Similarly, magnesium can be precipitated as magnesium hydroxide in a double displacement reaction.
The reactions involved are:
and .
Note: This Clark’s process is used to remove temporary hardness only. In the process, both the calcium and magnesium in the water and the calcium added with the lime are precipitated. But while removing permanent hardness, washing soda is added to chlorides and sulphates which get precipitated as magnesium and calcium carbonates. The reactions are
and .
Complete step by step answer:
Let us first discuss hard water first.
Hard water is a type of water in which mineral content is high. Hard water is formed when water percolates via the deposits of limestone, gypsum or chalk. It is made up of calcium and magnesium bicarbonates and sulphates.
There are two types of hardness in water, one is temporary hardness and other is permanent hardness.
(1) Temporary hardness: Temporary hardness is caused by the presence of dissolved bicarbonate salts like calcium bicarbonate and magnesium bicarbonate. These salts give calcium and magnesium cations
(2) Permanent hardness: It is usually caused by the presence of calcium chloride
The temporary hardness of water is due to bicarbonates only salts of calcium and magnesium.
So, the correct answer is “Option B”.
Additional Information:
There are many ways by which temporary hardness can be removed-
(1) Boiling: After filtration, the insoluble carbonates are obtained by boiling. The reaction is
(2) Clark’s process: Dissolved carbon dioxide
The reactions involved are:
Note: This Clark’s process is used to remove temporary hardness only. In the process, both the calcium and magnesium in the water and the calcium added with the lime are precipitated. But while removing permanent hardness, washing soda is added to chlorides and sulphates which get precipitated as magnesium and calcium carbonates. The reactions are
Recently Updated Pages
Master Class 11 Accountancy: Engaging Questions & Answers for Success

Master Class 11 Social Science: Engaging Questions & Answers for Success

Master Class 11 Economics: Engaging Questions & Answers for Success

Master Class 11 Physics: Engaging Questions & Answers for Success

Master Class 11 Biology: Engaging Questions & Answers for Success

Class 11 Question and Answer - Your Ultimate Solutions Guide

Trending doubts
The non protein part of an enzyme is a A Prosthetic class 11 biology CBSE

Which of the following blood vessels in the circulatory class 11 biology CBSE

What is a zygomorphic flower Give example class 11 biology CBSE

The deoxygenated blood from the hind limbs of the frog class 11 biology CBSE

What is the function of copulatory pads in the forelimbs class 11 biology CBSE

Which of the following is nitrogenfixing algae a Nostoc class 11 biology CBSE
