The product of the hydrogen ion and hydroxide ion concentrations in aqueous solution is a constant, 1.00 X 10-14.
Dividing this constant by the hydroxide ion concentration will give the hydrogen ion concentration:
`[H+] = (1.00x10^(-14))/([OH-]) = (1.00x10^(-14))/(5.03x10^(-13)) = 1.99x10^(-2)`
Choice b is therefore the correct answer, reported to two significant figures.
A solution that contains more hydrogen ions than hydroxide ions, as this one does, is acidic. If a solution contains more hydroxide than hydrogen ions it's basic. If [H+] = [OH-] the solution is neutral and the concentration of both H+ and OH- will be 1.00 X 10E-7.
The constant used here, 1.00 X 10-14, also written as Kw, is the equilibrium constant for the auto-ionization of water:
`H_2O_((l)) -> H^+_(aq) + OH^-_(aq)`
The equilibrium constant expression for this reaction is :
`K_w = [H+][OH-]`
The concentration of water is not included in the expression because it's a pure liquid and so its concentration remains relatively constant.
No comments:
Post a Comment