H_2Ais a weak diptotic acid . IF the pH of 0.1 MH_2Asolution is 3 and concentration of A^(2)is 10 ^(-12)"at "25 ^(@) CSelect correct statement (s)

H_2Ais a weak diptotic acid . IF the pH of 0.1 MH_2Asolution is 3 and

1.	H_2Ais a weak diptotic acid . IF the pH of 0.1 MH_2Asolution is 3 and concentration of A^(2)is 10 ^(-12)"at "25 ^(@) CSelect correct statement (s)
Answer» `[H^(+) ]_("total")~~[H^(+) ]` from first step ionization of acid `H_2A ` Concentration of `OH^(-) ` in solution is `10 ^(-3) ` M The value of `K_(a_1) `is NEARLY `10 ^(5)` `p^(ka_2)- p^(ka_1) =9` Solution :` [H^(+) ]=sqrt(K_(a_1) xx C ) rArr 10^(-3)=sqrt( K_(a_1)xx 10^(-1)) ` ` K_(a_1) =10 ^(-5) rArr [A^(-2) ]=K_(a_2) rArr P^(K_(a2 )) = 12 ` ` P^(K_(a2))-P^(K_(a3)) = 7 `