In A Doll House by Henrik Ibsen, how does the conflict move forward (develop further) in Act II?historical, social, cultural
(I am not permitted to address all of the areas you mention. This answer will address the social ramifications of what occurs in Act II.)
In Act II of Ibsen's A Doll House, several things occur to further develop the plot.
Nora tells Mrs. Linde that Krogstad is blackmailing her. (As the audience knows, if paying attention, Kristine Linde knows Krogstad; Nora's sharing of this secret becomes extremely important to the climax of the story.) Nora's signing for a loan in the name of her dead father has social ramifications: it is against the law.
Because of Nora's fear that Krogstad will tell her husband what she has done, she begs Torvald not to fire him. But because she has done so, her husband becomes ornery and fires Krogstad immediately. Without knowing it, he has actually endangered his marriage. In firing Krogstad, Torvald is making it nearly impossible for the man to survive within society. Krogstad has been trying to improve his reputation, recovering from past mistakes, and he has children to raise on his own. Torvald's action drives Krogstad to take rash steps to lash out at the Helmers.
When Nora tries to discuss her problem with Dr. Rank, she discovers he loves her, and she feels it would be inappropriate to ask someone who loves her, who is also a great friend of her husband, for assistance. Her teasing of Dr. Rank earlier had encouraged Rank to speak his mind. She feels that having done so, he has "ruined everything." Socially, it would be improper of her to continue her friendship with Rank as it has been, with her new knowledge of his feelings.
Torvald's aggressive action in firing Krogstad, drives Krogstad to put a letter in the Helmer's mailbox to guarantee that Torvald will finally know the truth of what Nora has done. Had it not been for Torvald's superior attitude where Krogstad was concerned, Nora might have been able to win more time to pay her debt. Krogstad takes this step, as mentioned earlier, because he will be destroyed socially now (probably unable to get another job) by Torvald's actions.
To keep Torvald from reading the letter, Nora acts like his "doll-wife," pleading for his help to better perform her dance for that evening's masquerade party. Acting quite helpless, Nora wins Torvald's agreement not to check the mail until after the party. All the while, Nora knows that her life as she knows it will be over when they return home from the gathering at their neighbor's flat.
Socially, a woman in this era was at the mercy of her husband. He could punish her as he saw fit. Torvald can throw Nora out on the street. We have learned from Mrs. Linde how impossible this kind of life is, and might assume that Nora could never survive such a situation.