Solutions
A homogenous mixture of substances that has uniform composition throughout is called homogenous mixture.
Example. A mixture of 10 g sugar dissolved in 100 g water.
Solute:
A substance that is present in lesser amount in a solution is called salute.
Example, In a solution og 10 g sugar dissolved in 100 g water, sugar is a solute.
Solvent
IA substance that is present in larger amount in a solution is called solvent.
Example, In a solution og 10 g sugar dissolved in 100 g water, water is a solvent.
Aqua solution
A solution in which water is s solvent is called aqua solution.
The word aqueous is drive from latin word Aqua meaning water.
Aquous solutions are frequently used to dis to disperse substances such as medicine.
Saturated solution:
A slution that cannot dissolve more salute at given temperature is called saturated station.
Unsaturated solution:
A slution that can dissolve more salute at given temperature is called saturated station.
Supersaturated solution;
A slution that contains more of salute that is present in saturated solution iat given temperature is called supersaturated station.
Question: How will you determine whether solution is saturated or supersaturated?
Answer.
A saturated solution is stable while supersaturated saturated solution is not . For example, if we add a crystal of sodium thiosulphate to its saturated solution, it will simply settle down without dissolving. On the other hand, if we add a crystal of sodium thiosulphate to its supersaturated solution,, crystallization will start. After complete crystallization, we obtain saturated solution.
Types of solutions
As solute and solvent can exist in any one of three states of matter, I.e., gas, liquid or solid. Solution can also exist in any one of the three states of matter the physical state of solution is same as that of solvent. There are some important types of solutions that we observe in our daily life.
1. Solutions of gases
2. Solutions of liquids
3. Solutions of solids
. Solutions of gases
Solution of gases are of three types:
I. When both solute and solvent are gases (gas in gas)
The gas which is present in large quantity is solvent and other is solute
e.g., Mixture of Nitrogen and hydrogen gases is used to prepare ammonia.
mixture of ammonia and CO2 is used to prepare urea.
ii.. When solute is a gas and solvent is a liquid (gasin liiquid )
e.g., Air (oxygen) dissolved in water is important for survival of fish and other aquatic life.
CO2 is redily dissolved in water and used as carbonated drinks.
iii. . When solute is a gas and solvent is a solid (gasin solid )
e.g., H2 gas adsorbed on the surface of finally divided Ni is used in food industry for conversion of oil into ghee. Here Ni acts as catalyst.
2. Solutions of liquids
Solution of liquids are of three types:
i.. When a solute is a liquid and a solvent is a gas (liquidin gas )
e.g., fog is a solution of water vapors in air(gas).
Clouds mist etc in both examples solute is water and solvent is gaseous state.
ii. When both solute and solvent are liquids (Liquid in liquid )
e.g., rectified spirit contains 5% ( by volume ) of water and 95% (by volume ) of ethyl alcohol. It is produced by fermentation of cane sugar.
Vinegar contains 5% (by mass) of acetic acid and 95% (by mass ) of water.
iii. . When a solute is a solid and a solvent is a solid (solid-liquid solution)
e.g., Amalgam ( a solution of any metal in mercury is called Amalgam).
Hg is only metal that is liquid at room temperature.
Silver amulgum (Silver dissolved in mercury) or tin amulgum
(tin dissolved in mercury) are widely used to make dental filling. They form a semi solid that can be shaped to fill cavity. On standing, they become hard and slightly expand and therefore tightly fit into cavity.
Solution of solids
Solution of solids are of three types:
I. When solute is a solid and solvent is a gas (solid in gas)
In this solution, solid particles are solute and gas is a solvent.
e.g., smoke that contains solid carbon particles as solute and air as a solvent.
ii.. When solute is a solid and solvent is a liquid (solid in iquid )
e.g., water obtaining minerals such as lime stone, NaCl etc
Common salt dissolved in water, sugar dissolved in water.
8.85 % (by mass) of NaCl dissolved in 99.15 % (by mass) of water is used intervenes solution that is given to persons suffering from dehydration
iii. . When solute is a solid and solvent is a solid (solid in solid )
For example alloys, i.e., Brass is alloy of copper and zinc. Steel is alloy of iron containing small amounts of carbon and silicon. In jewellery, copper is added to gold to make it harder as pure gold is very soft. Other examples are Ruby, Opal etc.
Concentration units
Concentration: The quantity of a solute present in a given amount of solvent are solution is called concentration of solution.
Dilute solution: A solution that contain a relatively low quantity of salute is called dilute solution.
Concentrated solution: A solution that contains relatively high quantity of solute is called concentrated solution.
Concentration in terms of Percentage and molarity
Percentage
The mass or volume of solute dissolve in 100 gm or 100 cm3 of solution is called percentage of solution.
% (m/m) : Mass in gram of slue dissolve in 100 gram of solution is called as %
(m/m) of solution. For example, if you dissolve 10 g of NaCl in 90 g of water to make 100 g solution, then concentration of solution will be 10 % m/m.
% (v/v) : Volume in cm3 of slute dissolve in 100 cm3 of solution is called as % (v/v).of solution. For example, if you dissolve 10 cm3 of ethanol in 90 cm3 of water to make 100 cm3 solution, then concentration of solution will be 10 % v/v.
% (m/v) : Mass in gram of slute dissolve in 100 cm3 of solution is called as %
(m/v) of solution. For example, if you dissolve 10 g of NaCl in sufficient water to make 100 cm3 solution, then concentration of solution will be 10 % m/v.
% (v/m) : Volume in cm3 of slute dissolve in 100 g of solution is called as % (v/v).of solution. For example, if you dissolve 10 cm3 of ethanol in sufficient water to make 100 cm3 solution, then concentration of solution will be 10 % v/v.
Molarity: Molarity is defined as the number of mole of slue dissolve for dm3 of solution.
Mathematically,
Molarity = no. of moles of solute/ volume of solution (dm3)
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