1-Naphtholbenzein Solution

1-Naphtholbenzein Solution A 0.2% w/v solution of 1-naphtholbenzein in anhydrous acetic acid.

Complies with the following test.

Sensitivity Add 0.25 mL of the solution to 50 mL of glacial acetic acid. Not more than 0.05 mL of 0.1m perchloric acid VS is required to change the colour of the solution from brownish yellow to green.