Prove that the dergee of dissociation of weak acid is given by:
`alpha = (1)/(1+10^(pK_(a)-pH))`
where `K_(a)` is its dissociation constant of the weak acid.

Prove that degree of dissocation of a weak acid is given by: alpha= (1)/(1+10^((pK_(a)-pH)) where K_a) si its dissociation constant.

The dissociation of weak electrolyte (a weak base or weak acid) id expressed in terms of Ostwald dilution law. An acid is a substance which furnishes a proton or accepts an electron pair whereas a base is proton acceptor or electron pair donor. Storonger is the acid weaker is its conjugate base. The dissociation constants of an acid (K_(a)) and its conjugate base are related by (K_(w)=K_(a)xxK_(b) , where K_(w) is ionic prodcut of water equal to 10-14 at 25^(@)C . The numerical value of K_(w) however increases with temperature. In a solution of an acid or base [H^(+)][OH^(-)]=10^(14) .Thus, the [H^(+)] in a solution is expressed as : [H^(+)]=10^(-pH) and pH+pOH=14 . Buffer solutions are the solutions which do not show appreciable change in the pH on addition of small amount of acid or base. Which of the following statements are correct? (P) At 25^(@)C,pH of 10^(-10)MNaOH is nearly 7. (Q) The degree of dissociation of a weak acid is given by (1)/(1+10^((pk_(a)-pH))) . (R) For weak electrolytes of polyprotic acid nature having no other electrolyte, the anion concentration produced in II step of dissocitation is always equal to K_(2) at reasonable concentration of acid. (S) The concentraion of amide ions produced during self ionisation of NH_(3) is equal to concentration of ammonium ions. Ostwld dilution law is valid for strong electrolytes.

pK_(a) of a weak acid is defined as :