Paper 1 October/November 2008 CHEMISTRY (9701/01) IGCSE

The solids sodium chloride and sodium iodide both react with concentrated sulfuric acid at room temperature.
With $NaCl$ , the products are $NaHS{O_4}$ and $HCl{\text{ }}$.
With NaI, the products are $NaHS{O_4},{\text{ }}HI,{\text{ }}{I_2},{\text{ }}S{O_2},{\text{ }}{H_2}O,{\text{ }}S$ and ${H_2}S$.
What is the explanation for this difference in products?