Explain the use of irony in this exchange from Romeo and Juliet: - Benvolio and...

The general name given to literary techniques that involve
surprising, intriguing, or amusing contradictions, irony falls into three
categories:

1. verbal irony in which words are used
   to suggest the opposite of their usual
   meaning


2. situational irony in which an event occurs that
   directly contradicts the expectations of the reader or the
   audience


3. dramatic irony in which there is a contrast
   between what a character thinks and what the reader or audience knows to be
   true.

In Act II, Scene 1 of Romeo and
Juliet, Mercutio and Benvolio seek Romeo, whom they believe is hiding, but
because they do not know of Romeo's new love Mercutio calls to him in the name of
Rosaline:

I
conjure thee by Rosaline's bright eyes,

By her high
forehead and her scarlet lip,

That in thy likeness thou
appear to us! (2.1.19-21)

It
is dramatic irony that is exemplified in this scene as
Mercutio teases Romeo about Rosaline, not realizing that Romeo no longer is lovesick and
Rosaline's name now means nothing to him, for he is instead infatuated with Juliet. 
And, when Benvolio says,

readability="12">

Come, he hath hid himself among these
trees,

To be consorted with the humorous
night.

Blind is his love, and best befits the dark.
(2.1.32-34)

his words, also,
exemplify dramatic irony as Benvolio, also, believes that Romeo is moody and hiding
because he is still upset over his rejection by Rosaline.