What is the correct order of enthalpy of dissociation of halogens?

Which of the following statements is incorrect regarding dinitrogen pentoxide?

What is the temperature at which orthophosphoric acid forms pyrophosphoric acid?

Which allotrope of phosphorus is the most reactive?

What are the complexes formed by nitric oxide with transition metals called?

Which of the following would instantly react with chlorine?

What is one method of qualitatively analyzing a given salt for presence of ammonia?

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