What is the situational irony in "The Story of an Hour"?

Situational irony occurs in a story when the outcome of an event is the opposite of what one expects. Two paired instances of situational irony create the structure of Kate Chopin's "The Story of an Hour," both hinging on Mrs. Mallard's heart trouble and her husband's life. 

The first sentence of the story introduces Mrs. Mallard's heart trouble, implying immediately that the news of her husband's death might precipitate a heart attack. Thus, the expectation...

Situational irony occurs in a story when the outcome of an event is the opposite of what one expects. Two paired instances of situational irony create the structure of Kate Chopin's "The Story of an Hour," both hinging on Mrs. Mallard's heart trouble and her husband's life. 

The first sentence of the story introduces Mrs. Mallard's heart trouble, implying immediately that the news of her husband's death might precipitate a heart attack. Thus, the expectation is solidified beyond what readers would already anticipate: a woman who learns of the untimely death of her husband in a train accident will be overcome with grief. The irony is that Mrs. Mallard, after retreating to her room ostensibly to grieve, finds herself experiencing joy instead. She imagines the years of freedom spreading before her and focuses on her unexpected but welcome liberation, rather than on her loss. 

The second instance of irony, which caps off the story, occurs when Mr. Mallard appears in the doorway. He has not died after all. Normally, a wife would greet such news and such an appearance with joy, relief, and even euphoria. Readers would expect the wife, when she finds out that her husband is still alive and sees him standing there, to rush to him, embrace him, and possibly weep for joy. Instead, Louise drops dead of a heart attack. Her reaction is so unusual, the doctor ascribes her death to "the joy that kills," which is ironic since it was not what really killed her.

The impact of Chopin's story depends on the skillful use of situational irony; Louise reacts to the news of her husband's supposed death (and is happy) and to his appearing before her alive and well (and dies) in the opposite fashion of what we would expect.