This question seems to infer that Edna committed suicide because she recognised she was not able to give her children what they needed. This text abounds with images of children that reinforce both the importance of Edna's children to her own life and also the way that she can be compared to a child because of her awakening. Actually, the text makes it very clear that Edna chooses to kill herself to escape the "soul's slavery" that her children represent. Note how they are described in the following quote:
The children appeared before her like antagonists who had overcome her; who had overpowered and sought to drag her into the soul's slavery for the rest of her days. But she knew a way to elude them.
It is hard to ignore the profoundly negative way in which the children are described, with the use of the word "antagonist" clearly showing the way that in Edna's mind they are pitted against her and her newfound identity and freedom. Edna recognises that her children threaten to return her to the roles of mother and wife that society has prepared for her, and which she has done everything she can to escape. In the end, her battle to live her life on her own terms meets too much opposition, and her "awakening" reaches its tragic and logical conclusion when she does the only thing she can to free herself from the restrictions of society forever: drown herself.