Mrs. Mallard is the protagonist in "The Story of an Hour." We only learn her first name at the end of the story (Louise). Explain why that is important to this story.

This is such a significant omission because Mrs. Mallard feels that she has only existed as Mrs. Mallard for so many years. She has devoted the majority of her life to caring for her husband. His will has been her will. His wishes have been her wishes. And, in hearing of his death, she suddenly feels a new lightness in her spirit: freedom. She contemplates:

There would be no one to live for her during those coming years; she could live for herself. There would be no powerful will bending hers in that blind persistence with which men and women believe they have a right to impose a private will upon a fellow-creature.

She has a visible and physical reaction at the thought of such freedom. Her heart beats faster, and she cries tears of joy.
She is about to embark on a life separate from her husband—a life where she can explore her own desires and passions; a life as simply Louise:

Her fancy was running riot along those days ahead of her. Spring days, and summer days, and all sorts of days that would be her own. She breathed a quick prayer that life might be long. It was only yesterday she had thought with a shudder that life might be long.

And then her prospects of freedom are over. Mr. Mallard unexpectedly appears at the door, and the devastation is too much for her to bear. Her heart stops, and she dies as Mrs. Mallard, tied for eternity to her husband—her freedom unattained.