Mass Percentage:
-The mass percentage of a component in a given solution is the mass of the component per 100gm of the solution.
-For e.g. If WA is the mass of the component A, WB is the mass of the component B in a solution. Then, Mass percentage of A in a solution =WA+WBWA×100
Volume Percentage:
-This unit is used in case of a liquid dissolved in another liquid.
-The volume percentage is defined as the volume of the solute per 100 parts by volume of solution.
-For e.g. If VA is the volume of component A present is Vsol volume of the solution. Then, Volume percentage of A in the solution =VsolVA×100
Strength of Solution:
-Strength of a solution is defined as the amount of the solute in gm, present in one litre of the solution.
-It is expressed as gL−1.
-Mathematically,
Strength=Volume of sol.n in litresMass of solute in gm
Molarity:
- Molarity of a solution is defined as the number of moles of solute dissolved per litre of solution.
- Molarity is expressed by the symbol M.
Molarity=Volume of solution in litresNo. of moles of solute
Or,
Molarity=mol masswt. of solute(in gm)×V1000
- It can also be expressed as,
Molarity=Molecular mass of the soluteStrength in gms per litre
Normality:
- Normality of a solution is defined as the number of gram equivalents of a solute dissolved per litre of the given solution.
- Normality is expressed by the symbol N.
Normality=Volume of solution in litresNo. of eq. of solute
Or,
Normality=eq.wtwt. of solute(in gm)×V1000
- It can also be expressed as,
Normality=Eq.wt of the solutestrength in gms per litre
Note:
Normality=Molarity×Eq.wt of soluteMolecular wt of solute
Molality:
- Molality of a solution is defined as the number of moles of solute dissolved in 1000gm of a solvent.
- Molality is expressed by the symbol m.
- Molality does not change with temperature.
- Mathematically,
Molarity=Eq. mass of soluteNumber of moles solute
Formality:
- It is the number of gram formula masses of solute dissolved per litre of the solution.
- It is denoted by the symbol F.
- In case of ionic compounds like KCl, CaCO3 etc Formality is used in place of Molarity.
- Mathematically,
Formality=Volume of solution in LitresNumber of Gram formula masses of solute
Mole Fraction:
- It is the ratio of number of moles of one component (solute or solvent) to the total number of moles of all the components (solute and solvent) present in the solution.
- It is denoted by the symbol X.
- Let us suppose that a solution contains two components A and B and suppose that nA moles of A and nB moles of B are present in the solution then,
Mole fraction of A;XA=nA+nBnA……..(i)
Mole fraction of B ;XB=nA+nBnB……..(ii)
Relationship on Volumetric Analysis:
1) Substance reacts by gm. equivalent:
-If substance A reacts completely with Bthen,
no. of gm. equivalent of A=no. of gm. equivalent of B
or, (Eq.wtwt.)A=(Eq.wtwt.)B (EW=1000N×V)
2) For Acid Base Titration:
3) Dilution Formula:
- V1S1=V2S2
- gm/l=Normality×Eq. wt=Molarity×Mol. wt
4) Mixing no. of acid or alkali solution:
- Final Normality, N=V1+V2+...VnV1N1+V2N2+...VnNn
5) Mixing of acid solution with alkali solution:
- If (V∗N)acid=(V∗N)base, solution is neutral.
- If (V∗N)acid>(V∗N)base, solution is acidic.
- If (V∗N)acid<(V∗N)base, solution is basic.
- For acid excess, final normality,
N=Va+VbVaNa−VbNb; a= acid and b= base.
- For base excess, final normality,
N=Va+VbVbNb−VaNa; a= acid and b= base.