The following information refers to questions 7 to 9. Some chemistry students were investigating the relationship between concentration and rate of reaction. In the investigation, different concentrations of hydrochloric acid

were added to a sodium thiosulfate solution to produce solid sulfur. This reaction was represented by the following equation. 2 \mathrm{H}^{+}(\mathrm{aq})+\mathrm{S}_{2} \mathrm{O}_{3}^{2-}(\mathrm{aq}) \rightarrow \mathrm{SO}_{2}(\mathrm{~g})+\mathrm{S}(\mathrm{s})+\mathrm{H}_{2} \mathrm{O}(\ell) A piece of paper with a cross drawn on it was placed under the reaction vessel. The time taken for the cross to disappear due to the formation of the solid sulfur was measured. The type of data collected, and the source of data are best characterized as А.qualitative and primary. В.qualitative and secondary. С.quantitative and primary. D.quantitative and secondary.