1. Solution:
The solution is a homogeneous mixture of two or more chemically non-reacting substances whose composition can be varied within certain limits.
2. Solute and Solvent:
The solution is present in the same physical state as that of the solvent.
In case the species forming a solution are all present in the same physical state then the component which is present in a smaller amount is called the solute and the other present in a larger amount is called the solvent.
3. Concentration:
The concentration of a solution is a measure of the amount of solute that has been dissolved in a given amount of solvent or solution
4. Types of concentration terms:
(I) Mass fraction or % (w/w)
The mass percentage of a component of a solution is defined as:
For example, if a solution is described by 10% glucose in water by mass, it means that 10 g of glucose is dissolved in 90 g of water resulting in a 100 g solution. Concentration described by mass percentage is commonly used in industrial chemical applications. For example, a commercial bleaching solution contains 3.62 mass percentage of sodium hypochlorite in water.
(II) Mole fraction: Commonly used symbol for mole fraction is x and subscript used on the right-hand side of x denotes the component.
It is defined as:
It is expressed by X for example, for a binary solution with two components A and B.
Here nA and nB represent moles of solvent and solute respectively. Mole fraction does not depend upon temperature as both solute and solvent are expressed by weight.
(III) Molality
It is the number of moles or gram moles of solute dissolved per kilogram of the solvent. It is denoted by 'm'.
(IV) Mass by volume percentage (w/V): Another unit that is commonly used in medicine and pharmacy is mass by volume percentage. It is the mass of solute dissolved in 100 mL of the solution.
(V) Molarity:
It is the number of moles or gram moles of solute dissolved per litre of the solution. Molarity is denoted by 'M'.
Moles = M V
In case the volume is given in ml then the millimoles of solute will be given by the above formula
M1V1 = M2V2
(VI) Normality
It is the number of gram equivalents of solute present in one litre of the solution and it is denoted by 'N'.
Normality Equation:
When a mixture of different solutions having different concentrations are taken the normality of the mixture is calculated as follows:
(VII) Strength :
It is the amount of solute present in one litre of solution. It is denoted by C or S.
(VIII) The relation between Normality and Molarity :
N = molarity x n-factor
N x Eq wt. = molarity x molar mass
Exam | Chapter |
JEE MAIN | Some basic concepts in chemistry |
What volume (in L) of solution of 2M BaSO4 contains 192 g of SO42- ion?
A. |
|
B. |
|
C. |
|
D. |
|
A sample of KCl is placed in 50 ml of solvent. What should be the mass (in gm) of the sample for the molarity to be 2M ?
A. |
|
B. |
|
C. |
|
D. |
|
A 10 mg effervescent tablet containing sodium bicarbonate and oxalic acid releases 0.25 ml of at T = 298.15 K and p = 1 bar. If the molar volume of is 25.9 L under such conditions, what is the percentage of sodium bicarbonate in each tablet?
[Molar mass of NaHCO3 = 84 g mol-1]
A. |
|
B. |
|
C. |
|
D. |
|
The amount (in g) of sugar required to prepare 2L of its 0.1 M aqueous solution is:
A. |
|
B. |
|
C. |
|
D. |
|
Calculate the molality of a solution containing of Acetic acid in Ethanol if the mass of solute = 10g and the density of Ethanol = 0.789 gmL-1.
A. |
|
B. |
|
C. |
|
D. |
|
A solution of sodium sulfate contains 92g of ions per kilogram of water. The molality of ions in that solution in mol Kg-1 is:
A. |
|
B. |
|
C. |
|
D. |
|
Ferrous sulphate heptahydrate is used to fortify foods with iron. The amount (in grams) of the salt required to achieve 10ppm of iron in 100kg of wheat is:__________
Atomic weight of Fe = 55.85; S = 32.00; O = 16.00;
A. |
|
B. |
|
C. |
|
D. |
|
An aqueous solution of NaCl is labelled as 10% (w/w). What is the molality of the given solution?
A. |
|
B. |
|
C. |
|
D. |
|
What would be the molality of 20% (w/w) aqueous solution of KI?
( molar mass of KI =166 g mol-1 )
A. |
|
B. |
|
C. |
|
D. |
|
8 g of NaOH is dissolved in 18 g of H2O. Mole fraction of NaOH in solution and molality (in mol kg-1) of the solution respectively are :
A. |
|
B. |
|
C. |
|
D. |
|
5 ml of 1 M HCl, 20 ml of 0.5 M H2SO4, 75 ml of 0.1 M HNO3 are mixed together. What is the molarity of H+ ions in the resulting solution?
A. |
|
B. |
|
C. |
|
D. |
|
Molarity of liquid with density equal to is
A. |
|
B. |
|
C. |
|
D. |
|
Hydrochloric acid solutions A and B have concentrations of 0.5 N and 01. N respectively. The volume of solutions A and B required to make 2 litres of 0.2 N hydrochloric are
A. |
|
B. |
|
C. |
|
D. |
|
The density of a solution prepared by dissolving 120 g of urea (mol. Mass = 60u) in 1000g of water is 1.15 g/mL. The molarity of this solution is:
A. |
|
B. |
|
C. |
|
D. |
|
What is the mole fraction of the substance A in the following mixture:
(A = 5 moles, B = 6 moles, C = 4 moles, D = 5 moles).
A. |
|
B. |
|
C. |
|
D. |
|
The normality of phosphorus acid is
A. |
|
B. |
|
C. |
|
D. |
|
The mole fraction of a solute in a 100 molal aqueous solution is _________ . (Round off to the Nearest Integer).
[Given: Atomic masses ]
A. |
|
B. |
|
C. |
|
D. |
|
molecules are present in of a substance The molarity of a solution containing of substance in solution is ______.
A. |
|
B. |
|
C. |
|
D. |
|
Dissolving 120 g of a compound of (mol. wt. 60) in 1000 g of water gave a solution of density 1.12 g/mL. The molarity of the solution is :
A. |
|
B. |
|
C. |
|
D. |
|
After completion of 75% of the reaction what would be the mole fraction for the constituents ?
A. |
|
B. |
|
C. |
|
D. |
|
Calculate the molarity of 0.450 N HCl.
A. |
|
B. |
|
C. |
|
D. |
|
is reacted with solution, the molarity of the resulting product in the solution is____________ millimolar. (Nearest integer)
A. |
|
B. |
|
C. |
|
D. |
|
What is the molality of a solution containing 222.6 g ethylene glycol(C2H6O2) in 200 g of water ?
A. |
|
B. |
|
C. |
|
D. |
|
The mole fraction of a solvent in aqueous solution of a solute is The molality of the aqueous solution is :
A. |
|
B. |
|
C. |
|
D. |
|
The molarity of HNO3 in a sample which has density 1.4 g/mL and mass percentage of 63% is ____ (in mol/L) (Molecular weight of HNO3 = 63).
A. |
|
B. |
|
C. |
|
D. |
|
What is the mole fraction of the solute in a 1.00 m aqueous solution ?
A. |
|
B. |
|
C. |
|
D. |
|
After completion of 75% of the reaction what would be the mole fraction for the constituents?
A. |
|
B. |
|
C. |
|
D. |
|
The concentration of a solution or the amount of substance present in its given volume can be expressed in several ways like mass per cent, mole fraction, molarity, molality.