Colourful Chemistry General Chemistry

What links litmus paper and lichens?

Along with universal indicator, litmus paper is one of the most commonly encountered pH indicators in school chemistry lessons. Unlike the range of colours produced by the former, litmus is pink-red in acidic solutions and blue in alkaline solutions. This graphic highlights its complex origins in lichens and the chemical changes that account for its […]

Chemistry History General Chemistry

Today in Chemistry History: Søren Sørensen and the pH scale

On this day (9th January) in 1868, Danish chemist Søren Sørensen was born. He’s best known for developing the pH scale, which we’ve likely all encountered, to measure the acidity or alkalinity of solutions. This graphic gives a brief overview of the pH scale and what it means.

Colourful Chemistry Food Chemistry

Making a Red Cabbage pH Indicator: The Method and the Chemistry

We all know examples of everyday substances that can be classified as acids or alkalis: lemon juice is acidic, bleach is alkaline, and so on. Another substance that can be found in your kitchen can be used to test other substances to determine whether they are acidic or alkaline. The chemicals that give red cabbage its […]

Colourful Chemistry

The Colours & Chemistry of pH Indicators

Most of us, chemists or otherwise, have probably come across pH indicators at one point or another. I’d be surprised if there’s anyone out there who hasn’t, back in school, carried out the standard experiment of adding universal indicator to a variety of household liquids to identify them as acidic or alkaline. You might not […]