Question

A 1.0 M solution of hydrochloric acid is mixed with an equal volume of sodium hydroxide solution. The resulting solution turns pH paper blue, meaning the solution is basic. Which of the following concentrations would be consistent with the experimental results for sodium hydroxide?

Answer 1

  From the net  equation     OH  ions plus   H  ions  to gives  water . OH-  ions  concentration  is  consistent  in  the  reaction   thus  the  resulting solution  turn  pH meter  blue. The  stoichiometry   of  sodium  hydroxide  reacting   with  hydrochloric  acid  doubles,  which  decreases the concentration   of  H  ions.

Answer 2

Given that the solution is basic means that the sodium hydroxide moles from the sodium hydroxide solution exceeded the number of moles of the hydrochloric acid solution.

Then, given that the volumes are equals you can set this inequality

Nbase * V base > Nacid * Vacid

Vbase = V acid => Nbase > Nacid.

So, the response is any solution whose concentration is greater than 1.0 M.