Answer to Question #21697 in Physical Chemistry for kamseudouglas

Question

calculate pH of pure water at 50 degree celcius

Answer 1

pH of pure water at room temperature is 7. The dissociation constant, K_W, has a value of 1.0*10^−14 at 25 °C, so in neutral solution both the hydrogen ion concentration and hydroxide ion concentration are 1.0*10^−7 mol/L.

The pH value of pure water decreases with increasing temperatures because the dissociation constant, K_W, is depending on the temperature: 7.94*10^-14. So the pH of pure water at 50 °C is 6.55. At that temperature both H⁺ and OH^- concentrations are 2.8*10^-7 mol/L

Answer: 6.55