which of these statements best explains why pure water has a ph of 7? pure water contains only h2o…

which of these statements best explains why pure water has a ph of 7? pure water contains only h2o molecules, but ph is based on the concentration of h3o+ ions. each molecule of water can dissociate to form 7 h3o+ ions. water self - ionizes to form an equilibrium system that has h3o+=1.0×10−7 m.

which of these statements best explains why pure water has a ph of 7? pure water contains only h2o molecules, but ph is based on the concentration of h3o+ ions. each molecule of water can dissociate to form 7 h3o+ ions. water self - ionizes to form an equilibrium system that has h3o+=1.0×10−7 m.

Answer

Answer:

Water self - ionizes to form an equilibrium system that has $[\text{H}_3\text{O}^+]=1.0\times 10^{-7}\text{ M}$.

Explanation:

Step1: Define pH formula

$pH = -\log_{10}[\text{H}_3\text{O}^+]$

Step2: Calculate pH of water

For pure water, $[\text{H}3\text{O}^+]=1.0\times 10^{-7}\text{ M}$. Substitute into formula: $pH=-\log{10}(1.0\times 10^{-7}) = 7$. Water self - ionizes as $2\text{H}_2\text{O}\rightleftharpoons\text{H}_3\text{O}^++\text{OH}^-$ and at equilibrium $[\text{H}_3\text{O}^+]=1.0\times 10^{-7}\text{ M}$, which gives a pH of 7.