• Question: When someone tells me to think of acid, I always picture it green, is this just a myth, or is there a type of thick green acid? If there is, what is it composed of to make it green?

    Asked by to Aimee, Chris, Dave, Greig, Laurence on 16 Jun 2014. This question was also asked by .
    • Photo: Greig Cowan

      Greig Cowan answered on 16 Jun 2014:

      The acid I used in my chemistry classes was always clear transparent. It was typically hydrochloric or sulphuric acid. I believe most acids are like this, but I’m sure you could add some sort of colouring to them to make it green if you want.

      Another option could be some acid-producing bacteria. The bacteria themselves could be green, such that when they produce the acid, the mixture of the two looks greenish.

    • Photo: Laurence Perreault Levasseur

      Laurence Perreault Levasseur answered on 16 Jun 2014:

      Chlorogenic acid is green when it oxidizes.
      It’s an antioxidant (the same as in the food ones, like peaches and prunes) , and it’s found in a lot of plants, like bamboo, and green coffee beans. It also goes into the ingredients of chewing gum (!!).
      However, before it gets oxidized, it doesn’t have any particular colour. It’s found in potatoes, and usually potatoes aren’t green.

      Nickel(II) chloride is also green in its most common (solid) form, and when dissolved in water. It’s relatively weak acid, but I think it’s very common, because it’s the most common nickel compound. How thick it is depends on how much of it you dissolve I guess 😉 you can look it up here:
      http://en.wikipedia.org/wiki/Nickel(II)_chloride

      In general, things that become acid when dissolved can have very different colours before they are dissolved. I think the reason we think about something green and bubbly when we think about acids comes from cartoons.

      Strong acids like sulphuric acids and nitric acids are transparent when they are dissolved in water, however.

    • Photo: Aimee Hopper

      Aimee Hopper answered on 19 Jun 2014:

      The thick green acid you are thinking of is what is generally shown in cartoons, but has no real scientific reasoning.

      Cartoon makers seem to think that people think something that is green and thick is gross (like flem you cough up if you’re ill), and acid is dangerous, so it’s just their way of making a scary substance that people can relate to.

      “Green” can be made in a number of different ways. Light with a wavelength of between 495 and 570 nm is “green”, and so anything that reflects or emits this will be considered green.

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