Why Does Hamlet Kill Polonius?

In Shakespeare’s play, Hamlet wants to kill his uncle Claudius because a ghost of Hamlet’s father has told Hamlet that his own brother Claudius has killed him by pouring poison in the ear. Hamlet wants revenge from the new king Claudius because he has gotten whatever the old King Hamlet had.
Hamlet comes to see his mother, without knowing that there is Polonius who hides behind the curtain and listens to their conversation. Hamlet tells Gertrude that he will not leave until he proved to her how bad Claudius is. Hamlet’s plan to act cruel towards his mother rattles Gertrude so thoroughly that it makes Polonius cry out for help too - resulting in Hamlet killing Polonius, while thinking it was Claudius. This murder sets into motion a sequence of killing and lethal plans. Hamlet’s inability to avenge the murder of his father drives the plot and ultimately leads to the deaths of many of the major characters, including Laertes, Claudius, Polonius, Gertrude, Ophelia and Rosencrantz and Guildenstern.
Hamlet’s pursue for justice for his father’s ‘most foul and unnatural murder’, leads to many deaths, including Polonius, who was murdered by a mistake.