Place these unknown pH test papers in order from most acidic to most alkaline. Four pH indicator strips.

In order of the colors of the pH test papers from most acidic solutions to most alkaline solutions, the colors of the pH test papers would be

               Red > Orange/Pink > Purple > Blue

(Red) Most acidic                                (Blue)Most alkaline

Explanation:

We can use the different colors of pH test papers to determine the acidity or alkalinity of a solution.

Definitions

A pH test paper is a strip of indicator paper which changes colour when placed in acidic or alkaline solutions.

A solution is said to be acidic if it turns the colour of the pH test paper RED

A solution is said to be alkaline/basic if it turns the colour of the pH test paper BLUE

Color changes

If the pH test paper turns red, then the solution is a very strongly acidic solution with pH less than 3 ( ie pH between 1-3)

If the pH test paper turns orange or pink, then the solution is a weak acidic solution with pH greater than 3 ut less than 7

If the pH test paper turns purple, then the solution is a weak alkaline solution with pH greater between 8-11

If the pH test paper turns blue, then the solution is a very strong alkaline solution with pH between 11 - 14

Summary

Therefore, in order of color changes from the most acidic solutions to most alkaline solutions, the colors of the pH test papers would be

Red > Orange/Pink > Purple > Blue

Most acidic                                Most alkaline