The OH- concentration in a 2.5 x 10-3 M Ba(OH)2 solution is A) 1.2 x 10^-2 M.
B) 2.5 x 10^-3 M.
C) 5.0 x 10^-3 M.
D) 4.0 x 10^-12 M.

Answer : C) 5.0 x 10^-3 M
if the concentration of Ba(OH)2 is 2.5 x 10^-3 M

then the OH- concentration is twice this so your answer is C.

It’s b. mass i searched it up

Answerδh > 0explanationc₆h₆  (s)  → c₆h₆ (l)if you are changing it from a solid to a liquid, you are pretty much melting the solid. this requires heat energy. therefore, the reaction is endothermic (takes in energy); the system enthalpy increases as the reaction proceeds: δh > 0.