Textbook Question 6A.21

[Jenifer_Fonseca]

Hello,

I am having a hard time understanding what the question is asking conceptually. For example where the square root came from. I received but I did not understand well.

[Alyssa_Miao_3B]

For this question, we use the equation Kw = [H3O+][OH-]. The reason why Kw is not equal to 1.0 x 10^-14 is because the reaction is not under standard conditions; the temperature is higher at 37 degrees Celsius which causes the Kw to deviate from the standard value. The problem says that the liquid we are looking at is water. Therefore, we know that in water, [H3O+] = [OH-]. This is why the question sets x^2 = 2.1 x 10^-14, since the two values would be equal to each other. So by taking the square root of Kw, that gives us both [H3O+] and [OH-].