Question

the ph scale
coffee
egg white
soda
water
ammonia solution
43.
a 3
b 5
c 7
d 9
e 11
according to the ph scale above, which of the following applies to the region labeled c?
the hydroxide ion concentration is equal to the hydrogen ion concentration in water.
the hydroxide ion concentration is more than the hydrogen ion concentration in water.
the hydroxide ion concentration is less than the hydrogen ion concentration in water.
there is not enough information to determine the concentration of either hydroxide or hydrogen ions in water

Explanation:

In the pH scale, a pH of 7 (like in region C, which is water) is neutral. In neutral water, the hydroxide ion ($\ce{OH^-}$) concentration is equal to the hydrogen ion ($\ce{H^+}$) concentration because the auto - ionization of water produces equal amounts of $\ce{H^+}$ and $\ce{OH^-}$ ions ($\ce{H_2O
ightleftharpoons H^+ + OH^-}$) at 25°C.

Answer:

The hydroxide ion concentration is equal to the hydrogen ion concentration in water.