Quick Answer: Blue Litmus Indicator Paper is cellulose paper treated with lichen-derived litmus dye that turns from blue to red in acidic solutions below pH 4.5. It comes as 100 leaves per pack in a 10mm x 75mm strip size.
Last updated: October 2026
Key Features
Blue litmus on absorbent cellulose paper
Turns from blue to red in acid (pH < 4.5)
Reacts on contact with acidic solutions
100 leaves per pack
Strip size 10mm x 75mm
Technical Specifications
Specification
Value
Indicator
Blue litmus, lichen-derived dye
Colour change
Blue to red (pH < 4.5)
Material
Absorbent cellulose paper
Quantity
100 leaves
Strip size
10mm x 75mm
About This Product
Blue litmus is the quickest test for an acid: a drop of the solution on the strip turns it red if the liquid is acidic, and leaves it blue if not. Used with red litmus paper, it lets students sort solutions into acids and bases in their first acid-base practicals.
Frequently Asked Questions
What colour change does Blue Litmus Indicator Paper show?
It turns from blue to red when it touches an acidic solution below about pH 4.5.
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