discuss the scope of ironies in the novel Gulliver's Travels ?

This novel is filled with irony and satire. In fact, it's FILLED with these things. There are examples in every chapter from the first page to the last, and it would take far too long to list those examples here;

Gradesaver has a fantastic study guide for this novel. Its link is the third provided under sources;

"Swift's major writing tools are irony and satire. As to the former, he relies mainly on situational irony rather than verbal or dramatic irony. In situational irony, a development, a result or an ending is the opposite of what one expects. For example, one would expect scientists and philosophers to be wise. But on the flying island of Laputa, they are woefully lacking in practical knowledge and even attempt to build a house from the roof down. Satire attacks or pokes fun at vices and imperfections. Throughout the novel, Swift satirizes kings, queens, politicians, military leaders, scientists, and thinks of the real world by implying or directly stating that they are like their counterparts in his fictional world." (1)

I have listed the link to an article below that cites many examples of irony and satire in detail. (2)