Chemistry
posted by Anna .
Estimate the equilibrium constant for the weak acid HCN, if a 4.68×103 M aqueous solution of HCN has a [H+] 0.00000151 M (make an exact calculation assuming that initial concentration is not equal to the equilibrium concentration).
HCN = CN + H+

............HCN ==> H^+ + CN^
I.........4.68E3....0.....0
C..........x........x......x
E........4.69E4x...x......x
Ka = (H^+)(CN^)/(HCN)
Ka = (x)(x)/(4.68E4x)
You know x = 1.51E6. Substitute into the above and solve for Ka.
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