Answer:
Conductivity meter
Explanation:
A conductivity meter is normally used to measure the amount of electrical current or conductance in a solution. Conductivity is most useful in determining the overall health of a natural water body.
A pH paper is used to determine the pH of a solution. This is done by dipping part of the paper into a solution of interest and watching the color change. The pH paper comes in a color-coded scale indicating the pH that something has when the paper turns a certain color.
An indicator is an organic compound that changes its colour depending on the pH of the solution.
Since neutralization reaction can only be monitored by monitoring the pH of the solution, a conductivity meter cannot be used to monitor the progress of a neutralization reaction since it does not monitor the change in pH of the system under study.
Answer:
3.14 grams of ammonium thiocyanate must be used to react completely with 6.5 g barium hydroxide octahydrate.
Explanation:

The balance chemical equation is :

Mass of barium hydroxide octahydrate = 6.5 g
Moles of barium hydroxide octahydrate = 
According to reaction, 2 moles of ammonium thiocyanate reacts with1 mole of barium hydroxide octahydrate. The 0.020635 moles of barium hydroxide octahydrate will react with:

Mass of 0.04127 moles of ammonium thiocyanate;

3.14 grams of ammonium thiocyanate must be used to react completely with 6.5 g barium hydroxide octahydrate