What tone characterizes Lady Catherine de Bourgh's attitude and behavior when she visits Longbourn?

I think you are referring to near the end of the story when Lady Catherine de Bourgh blunders in on Longbourn to warn Elizabeth against marrying Mr. Darcy. Elizabeth refuses her demands. Lady C is her arrogant domineering self. Elizabeth knows how to handle Lady C by now. Lady C is disgusted with Elizabeth which is natural for her when she doesn't get her way.