9. Kw is not constant with respect to temperature, but rather decreases as the temperature of the water decreases. At 10oC, Kw = 3.0 x 10-15. What is the pH of pure water at 10oC?
Given

[ H+ ] = [ OH- ]     and     Kw = [ H+ ] + [ OH- ]

and letting x = [ H+ ] , what is the correct substitution into the Kw expression?

a) Kw = x
b) Kw = 2x
c) Kw = x2
d) Kw = x3