AP Chemistry Question of the Day --54

Welcome back to my blog. Following is Question 53 I posted earlier. The correct answer is E.

53.  A solution appears yellow.  It must be absorbing in the  

    (a) yellow only    (b) red only    (c) green only    (d) blue only   (e) purple only.

I am always surprised when my students are confused with colours. As we know, the sunlight consists of UV, visible and infrared lights. The visible region is white (or colourless) when combined. It is actually a mixture of all the colours of the rainbow: red, orange, yellow, green, blue and purple. If a subject appears to be white, then it absorbs no visible light and reflects all the colours. If a subject appears to be black, then it absorbs all the colours of the visible region. If a subject appears a particular colour, for example yellow as stated in the above question, then it reflects only yellow light and absorbs the rest of the colours. The colour that was absorbed should be complimentary to yellow, which means when combined with yellow, it will be black. What colour is absorbed then:
There are three primary colours: red, yellow and blue, as shown below:

If only yellow light was reflected, then red and blue was absorbed and the combination of red and blue is purple. As a result, purple light was absorbed.

Following is question 54 of the series:














I will post the answer in my next blog.

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