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Physical Chemistry

Physical Chemistry-II

Non-Metals

Inorganic Chemistry

-The mass percentage of a component in a given solution is the mass of the component per $100$gm of the solution.

-For e.g. If $W_{A}$ is the mass of the component $A$, $W_{B}$ is the mass of the component $B$ in a solution. Then, Mass percentage of $A$ in a solution =$W_{A}+W_{B}W_{A} ×100$

-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 $V_{A}$ is the volume of component A present is $V_{sol}$ volume of the solution. Then, Volume percentage of $A$ in the solution =$V_{sol}V_{A} ×100$

-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=Volumeofsol.ninlitresMassofsoluteingm $

- Molarity of a solution is defined as the number of moles of solute dissolved per litre of solution.

- Molarity is expressed by the symbol $M$.

- Mathematically,

$Molarity=VolumeofsolutioninlitresNo.ofmolesofsolute $

Or,

$Molarity=molmasswt.ofsolute(ingm) ×V1000 $

- It can also be expressed as,

$Molarity=MolecularmassofthesoluteStrengthingmsperlitre $

- 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 $N$.

- Mathematically,

$Normality=VolumeofsolutioninlitresNo.ofeq.ofsolute $

Or,

$Normality=eq.wtwt.ofsolute(ingm) ×V1000 $

- It can also be expressed as,

$Normality=Eq.wtofthesolutestrengthingmsperlitre $

$Normality=Molarity×Eq.wtofsoluteMolecularwtofsolute $

- 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.massofsoluteNumberofmolessolute $

- 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 $KCl,CaCO_{3}$ etc Formality is used in place of Molarity.
- Mathematically,

$Formality=VolumeofsolutioninLitresNumberofGramformulamassesofsolute $

- 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 $A$;$X_{A}=nA+nBnA ……..(i)$

Mole fraction of $B$ ;$X_{B}=nA+nBnB ……..(ii)$

-If substance $A$ reacts completely with $B$then,

$no.ofgm.equivalentofA=no.ofgm.equivalentofB$

or, $(Eq.wtwt. )_{A}=(Eq.wtwt. )_{B}$ $(EW =1000N×V )$

- $V_{A}×N_{A}=V_{B}×N_{B}$

- $V_{1}S_{1}=V_{2}S_{2}$
- $gm/l=Normality×Eq.wt=Molarity×Mol.wt$

- Final Normality, $N=V_{1}+V_{2}+...V_{n}V_{1}N_{1}+V_{2}N_{2}+...V_{n}N_{n} $

- 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=V_{a}+V_{b}V_{a}N_{a}−V_{b}N_{b} $; a= acid and b= base.

- For base excess, final normality,

$N=V_{a}+V_{b}V_{b}N_{b}−V_{a}N_{a} $; a= acid and b= base.