Well one meaning of the word "writing" is the act of inscribing words on paper. So the use of paper is highly likely.
You can write in the test booklet but you are not allowed to use scratch paper.
Litmus paper
You can use a pH paper.
A litmus paper is a indicator that is used to test for acids or bases
The pH test paper is used to detrmine the pH; immerse a piece of paper in the solution and compare with the color scale.
A brown paper bag.
You can use in the school laboratory any type of pH paper.
use litmus paper
use to test the acid level in liquid.
Litmus paper will determine acid or base. Universal indicator paper (pH paper) will give an answer to the nearest whole number.
The simplest method is to use a pH paper.
by using an indicator like litmus paper!!!