Which is the correct statement regarding halogens?

Which oxide of nitrogen is released from car engines?

Which of the following oxide can act as both reducing and oxidising agent?

All halogens form only one oxoacid due to their high electronegativity and small size.

Which of the following is true regarding nitric acid?

Which of the following can classified as an amphoteric oxide?

How does PCl5 exist in its solid state?

Which of the following shows the correct sequence of acidic strength?