Report on Invisible Ink Activity 

St. John Junior College

Report on Invisible Ink Activity 

Focused on Acid-Base Reactions for 12th class chemistry lab conducted batch-wise:

Report on Invisible Ink Activity Demonstrating Acid-Base Reactions

Class: 12th Science
Subject: Chemistry
Venue: Chemistry Laboratory
Date: 10.06.2025
Conducted by: Mrs. Gurmeet Kaur / Ms. Vaibhavi Rathad

Objective:

To explore acid-base reactions using invisible ink and learn how chemical indicators can reveal hidden messages.

Introduction:

Invisible inks are substances that are initially invisible but become visible under certain conditions. 

In this activity, there was use of acid-base indicators and reactions to write secret messages that appear when exposed to another chemical – indicator, demonstrating the properties of acids, bases, and indicators.

Observations:

• Writing with NaOH solution – Base, was invisible while drying.
• Spraying with phenolphthalein  changes color
• The acid-base reaction was confirmed by the color change.

Conclusion:

The activity successfully demonstrated acid-base reactions and the role of indicators in detecting pH changes. It provided practical understanding of how invisible ink can be based on acid-base chemistry, making the learning process interactive and engaging.