Question

Part a what is the concentration of hydroxide ions in pure water at 30.0°c, if kw at this temperature is 1.47 × 10-14? what is the concentration of hydroxide ions in pure water at 30.0°c, if kw at this temperature is 1.47 × 10-14? 1.21 × 10-7 m 1.30 × 10-7 m 1.47 × 10-7 m 8.93 × 10-8 m 1.00 × 10-7 m

Answer 1

when the solution is pure water so,

Kw = [OH-][H3O+]

when [OH-] = [H3O+] we can assume both = X

and Kw = 1.47 x 10^-14 

by substitution:

1.47 x 10^-14 = X^2

∴ X = √(1.47 x 10^-14)

       = 1.2 x 10^-7 M