Reaction of chloroform, resorcinol and strong base A common reaction used to identify resorcinol (benzene-1,3-diol) in the laboratory is to react it with chloroform in presence of 30% sodium hydroxide (NaOH). A red coloured solution (or precipitate) is produced. I have searched many books and websites, but none of them give any clue about the actual reaction, its products, far less the reaction mechanism.

The reaction is as follows:

$$\ce{Resorcinol + Chloroform + 30\% NaOH -&gt; Red Colour}$$

So any ideas about what reaction is taking place?
Well, turns out to be, the reaction proceeds to product a red colored species.


  Reaction with chloroform in the alkaline medium
  
  Dissolve 0.1 g in 1 ml of water R, add 1 ml of strong sodium hydroxide
  solution R and 0.1 ml of chloroform R, heat and allow to cool. An
  intense, deep-red colour develops which becomes pale yellow on the addition of a slight excess of hydrochloric acid R.