2 mL of ethanoic acid was taken in test tube I and test tube II each. A red litmus paper was introduced in test tube I and a pH paper was introduced in test tube II. The experiment was performed by four students W, X, Y and Z; and they reported their observation as given in the table.

Students	Action on red litmus paper	Action on pH paper
W	Turned blue	Turned pink
X	Remains unchanged	Turned green
Y	Turned blue	Turned blue
Z	Remains unchanged	Turned pink

Which students observation is correct?

1. W
2. X
3. Y
4. Z

Z

Reason — Red litmus paper remains unchanged in ethanoic acid, while pH paper turns pink in acidic solution.