What is the relationship between Mrs.Linde's arrival and Nora's awakening and transformation?

Mrs. Linde and Nora are old friends. During their conversation, Nora shares her money problems with her old friend.... problems that have been a secret. Nora's reasons for sharing are twofold. She has another woman to talk to, and she has an opportunity to demonstrate her ability to not onlt take care of the family, but to conduct business as well.