Water and its types - class-XI
Description: water and its types | |
Number of Questions: 104 | |
Created by: Manjit Singh | |
Tags: evs properties of water chemistry water hydrogen hydrogen and its compounds experiments with water hard water and soft water |
A sample of water which freely lathers with soap solution is called hard water.
A sample of water which starts lathering with soap solution on boiling is called temporary hard water.
Which of the following has a low calcium and magnesium content?
What is hard water?
Permanent hardness can be removed by simple boiling it.
.................. water does not lather with soap
Boiling hard water with washing soda removes permanent hardness.
If a boiled and filtered hard water is added to soap and it lathers, the water is :
Types of hardness of water is :
What is the advantage of using detergents over soap in hard water?
The given sample of lathers easily with water, it is :
A cloudy or milky appearance characterizes :
Permanent hardness of water can be removed by :
A soap is :
Sodium salts of sulphonic acid are :
Washing soda soften both temporal and permanent hardness by :
Water which gives lather with soap easily is called as :
Which of the following is/are soluble in water?
Which of the following is denser than water?
Chemically calgon is:
Which of the following substance is not present in clear water?
Identify the substance that is not a water softener.
............ process is used for the removal of hardness of water.
Hard water can be softened in ?
Sodium hexa-metaphosphate is known as:
One litre of a sample of hard water contain $4.44mg$ $Ca{Cl} _{2}$ and $1.9mg$ of $Mg{Cl} _{2}$, what is the total hardness in terms of ppm of $Ca{CO} _{3}$ :
Temporary hardness can be removed by:
Permanent hardness of water can be removed by:
Hard water causes _________ .
Salts of calcium and magnesium like ___________ cause harness of water.
If 10 g of a sample of water contains 16.2 g of $ Ca(HCO _{3}) _{2} $, then the hardness of water is:
The hardness of water due to $ HCO^{2-} _{3} $ is 122pm. Select the correct statement(s).
Temporary hardness maybe be removed from water by adding?
Permanent hardness in water is due to the presence of:
The reagent commonly used to determine hardness of water is:
Which of the following ions present as impurity cannot be removed by calgon process ?
Which one of the following process will produce hard water?
Unstable hardness of water is due to the presence of:
Temporary hardness of water can be removed by
In a sample of temporary hard water which of the following water softening process does NOT produced any precipitate of cation responsible for hardness ?
One litre hard water contains $12 mg\, Mg^{2+}$ milli-equivalent of washing soda required to remove its hardness is:
Which of the following pair of ions makes the water hard?
Hardness of water is estimated by simple titration with
In water:
$Na _2CO _3$ is widely used in softening of hard water. If 1 L of hard water required $0.0106 g$ of $Na _2CO _3$, The hardness in ppm (parts per million i.e., $10^{6}$ ml) of $CaCO _3$ is:
A volume of 100 L of hard water requires 5.6 g of lime for removing temporary hardness. The temporary hardness in ppm of CaCO3CaCO3 is:
Which element has variable covalency?
$ RH _{2} $ (ion exchange resin ) can replace $ Ca^{2+} $ in hard water as :
$ RH _{2}+Ca^{2+}\rightarrow RCa+2H^{+} $.
One litre of hard water after passing through $ RH _{2} $ has pH = 2. Hence, hardness in ppm of $ Ca^{2+} $ is:
In a laboratory, hard water, required for an experiment, is not available. However, the following salts are available in the school laboratory :
1. Sodium sulphate
2. Calcium sulphate
3. Magnesium chloride
4. Sodium chloride
5. Calcium chloride
6. Potassium sulphate
Which of the above salts may be dissolved in water to obtain hard water for the experiment?
Both temporary and permanent hardness in water is removed by:
Both temporary and permanent hardness is removed on boiling water with :-
Hard water can be used:
Calgon is an industrial name given to____________.
Temporary hardness of water can be removed by :
The exhausted permutit is regenerated by treating sodium hydroxide solution in Clark's method for removing permanent hardness.
Calgon removes hardness by forming complex compounds with the $Ca^{2+}$and $Mg^{2+}$ ions of hard water or by adsorption.
The density of water is not same at all temperatures because of its anomalous expansion. The density is maximum at:
Calgon is an artificial zeolite for removing permanent hardness.
Sodium carbonate softens permanent hard water.
Presence of magnesium chloride in water makes it temporary hard.
Temporary hardness of water can be removed by:
The temporary hardness is caused due to:
Calcium bicarbonate in water makes it permanently hard.
Permanent hardness of water is due the presence of:
Hardness of water can be removed by :
Temporal hardness can be removed by just boiling the water because :
The reddish brown stains when clothes are washed with hard water is due to :
Calgon used as water softner is:
Water which doesn't give lather immediately with soap is called soft water.
At ________ $^0C$ water has its maximum density and its minimum volume.
Hardness of water is mainly due to the dissolved salts of ________ and ________.
We can cook pulses easily in hard water.
In permanent hardness of water, when washing soda is treated with water, ________ is precipitated out.
Hardness of water is due to soluble salts:
Calcium and Magnesium salts like _______ cause hardness of water
Hard water is unfit for laundries because:
What is the mass of a mole of water containing 50% of heavy water $(D _2O)$?
What happens on adding salt to the water in which eggs are boiled?
Water is liquid at room temperature, the most important reason for this is the :
Which of the following is true?
One litre of a samle of hard water contains 1 mg of $CaCl _2$ and 1 mg of $MgCl _2$.Then the total hardness in terms of parts of $CaCO _3$ per $10^8$ parts of water by mass is:
100 ml of tap water containing $Ca(HCO _3) _2$ was titrated with N/50 $HCl$ with methyl orange as indicator. If 30ml of $HCl$ were required, calculate the temporary hardness as part of $CaCO _3$ per $10^6$ parts of water.
The density of water is less in its solid state because:
The formula of calgon is:
The process used for the removal of hardness of water is:
Which of the following is not a disadvantage of using hard water?
Polyphosphates like sodium hexametaphosphate (calgon) are used as water softening agents because they:
A water sample is said to contain permanent hardness if water contains:
Which of the following compounds is used for water softening?
The brownish-white deposit on kettles, heating elements and utensils formed by boiling water is due to:
What is meant by demineralised water?
Permanent hardness is due to presence of soluble salts of Mg and Ca in the form of chlorides and sulphates in ${H} _{2}O$. It can be removed by:
Which of the following ions will cause hardness in water sample?
Permanent hardness is due to the presence of soluble salts of Mg and Ca in the form of chlorides and sulphates in ${ H } _{ 2 }O$. It can be removed by:
$6$ ml of a standard soap solution $(1$ ml $= 0.001$ g$)$ of $CaCO _{3}$ were required in titrating $50$ ml of water to produce a good lather. Its degree of hardness is:
(iii) causes temporary hardness of water
(iv) can be obtained in solid-state
Calculate the temporary and permanent hardness of water sample having the following the following constituents per litre:
$ Ca(HCO _{3}) _{2} = 162\, mg, MgCl _{2} = 95 =\, mg, $
$ NaCl = 585\, mg, Mg(HCO _{3}) _{2} = 73\, mg, $
$ CaSO _{4} = 136\, mg $
One litre of a sample of hard water contains 55.5 mg of $CaCl _2$ and 4.75 mg of $MgCl _2$. The total harness in terms of ppm of $CaCO _3$ is :
In a permutit, the calcium and magnesium ions of hard water are exchanged by:
The molecular formula of a commercial resin used for exchanging ions in water softening is $C 8H _7SO _3 $ (Mol. wt. 206). Water would be the maximum uptake of $Ca^{2+} $ ions by the resin when expressed ____ in mole per gram of resin.
The formula for permutit or zeolite which is used as softer in ion-exchange method is: