How plausible do you find bianca's flinging the handkerchief at cassio just when othello is looking on? how important is the handkerchief in this play? what does it represent? what suggestions or hints do you find in it?

Part of Shakespeare is just accepting that some things happen by coincidence to move the story forward. Bianca flinging the handkerchief at Cassio is one example of this. It might not be perfectly plausible, but it is definitely necessary. The handkerchief represents Desdemona's fidelity and Othello seeing it in another woman's hand from the man he thinks Desdemona is having an affair with, solidifies Iago's suggestion of the affair. The handkerchief represents Desdemona's innocence and when he sees it, her possibility of innocence is shattered.