In the story ''Lamb to the slaughter'', what types of irony are used in the story?

All three examples of irony are evident in "Lamb to the Slaughter."

The verbal irony is found in the title of the story. The phrase "Lamb to the Slaughter" suggests an innocent creature about to undergo torture and death. Mary Maloney could represent such a creature, and she would have met a similar fate if she had been found guilty of killing her husband.

More verbal and situational irony is represented in the murder weapon and what happens to it, unbeknownst to the people investigating the scene of the crime.

The murder weapon is a frozen leg of lamb. Mary hits her husband with it after mentally "snapping" when he announces to her that he will leave her. The hit kills him instantly. Shortly after, Mary comes up with a way to dispose of the murder weapon: she cooks it. What's more, she feeds it to the policemen who come to investigate the scene.

As the audience, we know what is going on. The characters do not. That would be the dramatic irony. We realize that they are eating the very thing they need to find in order to apprehend the person guilty of killing their fellow policeman, Patrick Maloney. They even comment that the murder weapon could be right "under their noses," which it is.

Meanwhile, in the other room, Mary Maloney giggles at the situational irony of it all. The lamb, after all, saved her from the slaughter of what could have been a death sentence, or life in jail as a pregnant woman.