Question

Which method helped you prove this hypothesis? Check all that apply.

Using various concentrations of HCl and NaOH to measure a range of pH

Using an existing scale to determine pH

Knowing that the cabbage indicator always has the same color at a given pH value

Answer 1

- Using various concentrations of HCl and NaOH to measure a range of pH — ✔
(This creates known pH points to test the indicator across the scale.)

- Using an existing scale to determine pH — ✔
(A pH meter or standard pH paper gives reference values to compare the cabbage colors to.)

- Knowing that the cabbage indicator always has the same color at a given pH value — ✖
(That’s an assumption/premise, not a method. You need to verify reproducibility experimentally rather than just assume it.)