Answer:
A Doll’s House is full of dramatic irony. For example, Nora expresses her happiness at the beginning of the play by saying that her husband is employed in a higher post and they need not to worry about their future. But, we see that all that was actually the expression of the hidden anxiety for the lack of money to pay off her debts to Krogstad. Nora has been poor. In fact, she is not so conscious of this reality. Ironically, all the troubles and sorrows of Nora begins with her husband promotion and her life is completely shattered at the end. She is unconscious about the future, and of course, we also do not know, that her expectation subsequently goes astray.
The situation when Helmer talks about the moral degradation of Krogstad is also ironical. Helmer explains that Krogstad had committed earlier a forgery and he was crooked by soul. He teaches Nora that she must not ask him to consider Krogstad’s case because such people contaminate their family and children with the influence of their guilt. Though Helmer is ignorant of the fact, Nora and readers come to know that, ironically, all his moral teachings were applicable to his own wife, Nora, who has also committed a similar crime of forgery.
It is also a case of dramatic irony when Helmer says that he will willingly sacrifice his happiness and dignity if some danger were to threaten his wife. But when such a thing happens in the next moment, he turns out to be a complete coward and an utterly egoistic person who will not sacrifice anything at all, in the name of a mere wife. The two dialogues from his own mouths will show the irony; one is his fanciful promise and the other is his response to the ensuing situation.