Weak acids dissociate partially in aqueous medium. If any common ion is present in the solution, the degree of dissociation of the acid is suppressed however the dissociation constant value remains constant. What is the degree of dissociation of water is 0.0IM HCOOH (K_(a) = 10^(-6)) at 25^(@) C?

Weak acids dissociate partially in aqueous medium. If any common ion i

1.	Weak acids dissociate partially in aqueous medium. If any common ion is present in the solution, the degree of dissociation of the acid is suppressed however the dissociation constant value remains constant. What is the degree of dissociation of water is 0.0IM HCOOH (K_(a) = 10^(-6)) at 25^(@) C?
Answer» ` 1.8 xx 10 ^(-12) ` ` 1.8 xx 10 ^(-14) ` ` 0.8 xx 10^(-12) ` ` 3.6 xx 10^(-10 ) ` Solution :From acid , ` [H^(+) ] =sqrt( K_a. C) rArr [H^(+) ] =10 ^(-4) M` ` " at "25^(@) C ,K_W =[H^(+) ] [OH^(-) ]` ` 10 ^(-14) =(10 ^(-14))[OH^(-)]` ` [OH^(-) ]=10 ^(-10) M` , In water `[H^(+) ] =10 ^(-10)M` ` alpha =( 10 ^(-10))/( 55.5 )rArr alpha = 1.8 xx 10 ^(-12) `