The independent variable is the variable being changed. In this case, the independent variable is the calculators. The dependent variable is essentially what you are looking for that <u>depends</u> on the independent variable. In this case it would be time. The constant variable or controlled variable are something that doesn't change and would skew the results. One may be the exact same problem for both groups. Try to come up with two more.
Since the solution have an observable color, that means that it absorbs light in the visible region hence it can be determined by colorimetry. Secondly, KMnO4 is a reducing agent which can be titrated against an oxidizing agent and it's concentration accurately determined.
The replacing of sodium hydroxide with potassium hydroxide
(KOH) to the reaction will least affect the organic product that forms.
Potassium hydroxide is an
inorganic compound with the formula KOH, and is commonly called caustic potash. Along with sodium hydroxide, this colorless
solid is a prototypical strong base.