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Water ionizes by the equation H2O(l)?H+(aq)+OH?(aq) The extent of the reaction i

ID: 811830 • Letter: W

Question

Water ionizes by the equation

H2O(l)?H+(aq)+OH?(aq)

The extent of the reaction is small in pure water and dilute aqueous solutions. This reaction creates the following relationship between [H+] and [OH?]:

Kw=[H+][OH?]

Keep in mind that, like all equilibrium constants, the value of Kw changes with temperature.

1) What is the H+ concentration for an aqueous solution with pOH = 4.18 at 25 ?C?

2) Arrange the following aqueous solutions, all at 25 ?C, in order of decreasing acidity.

0.0023M HCL, 0.0018M KOH, ph=5.45, pOH=8.55

3) At a certain temperature, the pH of a neutral solution is 7.61. What is the value of Kw at that temperature?

Explanation / Answer

1) 1.51 x10^-10

2) 0.0023M HCl > ph=5.45= pOH=8.55>0.0018M KOH (ph=5.45 and pOH=8.55 same acidic strength)

3) Kw= 6.0025 x 10^-16