please help me in the above given quedtions in picture
Answers
1.The simple definition of water hardness is the amount of dissolved calcium and magnesium in the water. Hard water is high in dissolved minerals, largely calcium and magnesium. ... When hard water is heated, such as in a home water heater, solid deposits of calcium carbonate can form.
2.Permanent hardness (mineral content) is generally difficult to remove by boiling. If this occurs, it is usually caused by the presence of calcium sulfate/calcium chloride and/or magnesium sulfate/magnesium chloride in the water, which do not precipitate out as the temperature increases.
3.Permanent Hardness of Water:
Permanent Hardness of Water:We can remove this hardness by treating the water with washing soda. Insoluble carbonates are formed when washing soda reacts with the sulfide and chloride salts of magnesium and calcium and thus hard water is converted to soft water.
4.There are two types of water hardness, temporary and permanent. Permanent hardness is due to calcium and magnesium nitrates, sulphates, and chlorides etc. This type of hardness cannot be eliminated by boiling.
5.Soft water is surface water that contains low concentrations of ions and in particular is low in ions of calcium and magnesium. ... The term may also be used to describe water that has been produced by a water softening process although such water is more correctly termed softened water.
6.Temporary hardness is a type of water hardness caused by the presence of dissolved bicarbonate minerals (calcium bicarbonate and magnesium bicarbonate). The presence of the metal cations makes the water hard.
7.Disadvantages of hard water
Disadvantages of hard waterHard water reaction with soap. ...
Disadvantages of hard waterHard water reaction with soap. ...Hard Water effect on Hair.
Disadvantages of hard waterHard water reaction with soap. ...Hard Water effect on Hair.Effect of Hard Water on skin – Due to high content of minerals in hard water it is very difficult for other substances to dissolve like soaps etc.
8.Temporary hardness is due to the presence of calcium hydrogencarbonate Ca(HCO3)2(aq) and magnesium hydrogencarbonate Mg(HCO3)2(aq). Both calcium hydrogencarbonate and magnesium hydrogencarbonate decompose when heated. The original insoluble carbonate is reformed. This happens when water is boiled.
9.Anhydrous or fused calcium chloride is highly hygroscopic in nature it readily absorbs moisture, also it is deliquescent in nature and is therefore used as a drying agent in a desiccator.
10. (i)A hygroscopic substance is one that readily attracts water from its surroundings, through either absorption or adsorption. Examples include honey, glycerin, ethanol, methanol, concentrated sulfuric acid, and concentrated sodium hydroxide (lye).
(ii)An efflorescent substance is a chemical which has water associated with its molecules, and which, when exposed to air, loses this water through evaporation. A common example of this phenomenon is the drying of cement.
(iii)Examples of Deliquescent Substances
Examples of Deliquescent SubstancesMost deliquescent substances are salts. Examples include sodium hydroxide, potassium hydroxide, ammonium chloride, gold(III) chloride, sodium nitrate, and calcium chloride.
11.washing soda (Na2CO3. 10H20) is efflorescent in nature. when exposed to air , it loses its water of crystallization and hence there is a loss of weight.
12.Common salt is NaCl with impurities of MgCl2. This MgCl2 is deliquescent, which on exposure to air absorbs moisture and gets converted to saturated solution. Thus, common salt becomes wet during rainy season.