Degree of dissociation of weak electrolyte at infinite dilution Why the degree of dissociation of weak electrolyte is 1 at infinite dilution and how do we get the result? Like I know that at infinite dilution the concentration of solution is 0 but what does that have to do with degree of dissociation, secondly in oswald's law of dilution we already assume that dissociation is almost negligible so we can't obtain the result from that also
There are a number of ways to explain this. In words, the entropic gain with dissociation overwhelms any attraction between counterions as the electrolyte is diluted. 

Mathematically: for a m:n electrolyte undergoing dissociation according to the reaction

$$\ce{A_mB_n -&gt; mA^{\nu_A -} + nB^{\nu_B +}}$$

if the initial concentration of electrolyte $\ce{A_mB_n}$ is $c_{T}$, define the degree of dissociation as

$$\alpha = \frac{c_{AB}}{c_{T}}$$

where $c_{AB}$ is the concentration of dissociated $\ce{A_mB_n}$. Assuming ideality and unit molarity as standard concentration, the equation for the equilibrium constant can be written as $$K=\frac{c_A^m c_B^n}{c_{AB}}$$ and solved in terms of the degree of dissociation. For a 1:1 electrolyte this leads to 

$$\alpha = \frac{\beta}{2}\left[\left(1 + \frac{4}{\beta} \right)^{1/2} -1\right] \tag{1}$$ 

where $\beta = K/c_T$. As $c_T \rightarrow 0$ it follows from this last expression that $\alpha  \rightarrow 1$ #QED

PS The following equation (from Wikipedia's page on Ostwald's law of dilution) $$\alpha=\sqrt{\frac{K}{c_T}} \tag{2}$$ does not hold over the entire concentration range $c_T$. It can be obtained from Eq. (1) by assuming $K&lt;&lt;1$ and therefore $\beta&lt;&lt;1$. For increasingly dilute solution Eq. (2) fails and  $\alpha  \rightarrow 1$.