Van't Hoff factor of 70% dissociated MgCl₂ solution is

Examples…..M₂SO₄(Na₂SO₄, K₂SO₄ etc), M₂CO₃(Na₂CO₃, K₂CO₃ etc) ;

They all are classified as ‘A₂B’ type electrolytes…..${\mathrm{A}}_2\mathrm{B} \rightleftharpoons 2{\mathrm{A}}^{+}+{\mathrm{B}}^{2-} ;$ n=3

                     Van't Hoff factor, i = $1-\mathrm{\alpha }+\mathrm{n\alpha }$ ;

    when n= 3 

                    Van't Hoff factor, i = $1+2\mathrm{\alpha }$ ; 

n=3….for AB₂(bi-univalent electrolyte)…...${\mathrm{AB}}_2 \rightleftharpoons {\mathrm{A}}^{2+}+2{\mathrm{B}}^{-} ;$ n=3

Examples…..MX₂(BaCl₂, CaCl₂ etc), M(NO₃)₂ (Ba(NO₃)₂, Ca(NO₃)₂ etc)

$\mathrm{\alpha }$= Degree of ionization  (or) dissociation ;

Ex ; For 5% ionized electrolyte  $\mathrm{\alpha }=\frac{5}{100}= 0.05 ;$

0.1, 0.15, 0.2, 0.25, 0.3…..for 10%, 15%, 20%, 25%, 30% ionized electrolyte

$\mathrm{\alpha }$ for x% electrolyte = $\frac{\mathrm{x}}{100}$; 

For AB₂ or A₂B type : i= 1+2$\mathrm{\alpha }$ ;

i= a) 1.1….5% ionized  b) i= 1.2…..10% ionized c) i=1.3….15% ionized d) i= 1.4…..20% ionized…..

Hint: For every 5% increase in ionization i.e for every 0.05 units increase in $\text{'}\mathrm{\alpha }\text{'}$ value ‘i’ increases by 0.1 units ;