Which is the correct statement regarding halogens?

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

Which is the most abundant group 16 element?

Which oxoacid of sulfur is commonly used for disinfecting swimming pools as well as delignification of wood?

What is the oxidation state of phosphorus in hypophosphoric acid?

In contact process, arsenic impurity has to be removed before proceeding.

What is the total number of atoms or groups surrounding each phosphorus atom in its oxoacids?

Sulphuric acid is called the ‘King of Acids’.