In "The Story of an Hour," how is the (assumed) death of Mrs. Mallard's husband shown to be an act of liberation of female voice and identity?

To answer this question you need to focus on and analyse the
impact of the death of Mr. Mallard on his wife, Mrs. Mallard. After the initial shock of the
news, Mrs. Mallard sits in her room and some kind of realisation or epiphany comes to
her:

When she abandoned
herself a little whispered word escaped her slightly parted lips. She said it over and over under
her breath: "free, free,
free!"

Although she fears this is a
"monstrous joy," she quickly dismisses this idea and we are shown how oppressed and stifled she
was as a woman through her marriage in a patriarchal society. It wasn't that her husband beat her
or deliberately mistreated her, but her new-found situation makes her realise how much she had
not been free:

There
would no be one to live for her during those coming years; she would 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.

It is this discovery
of freedom on the part of Mrs. Mallard that makes this short story so profound in terms of it
being an act of female liberation - Mrs. Mallard comes to see how restrictive marriage is and
begins to look forward to her new stage of life where she can "live for herself" without feeling
subjected to a patriarchal institution. No wonder, then, that having made this discovery, the
sudden return to it should be enough to shock her into death.