Cassius placed the old, worn research notes at the center of the table. The students clustered around, eyes scanning the faded ink, trying to make sense of the fragmented information. Some of the pages were missing, others smudged or torn, making the puzzle all the more difficult.

  “We could just do a confirmatory test for chloride on every vial,” suggested a younger student.

  Cassius shook his head. “That would take too long. Some of the reagents needed for confirmatory tests are limited, and we don’t even know if we have them all. We need a smarter approach.”

  Valencia ran her fingers over a portion of the notes, reading aloud. “First, eliminate unnecessary variables.” She frowned. “That means we have to narrow down the number of possibilities first.”

  Aether, a tall student known for his keen logical mind, traced a finger over another segment of the notes. “Look at this part… it mentions using an acid to test reactivity. If we recall from our earlier lessons, strong acids can donate hydrogen ions to an anion, sometimes creating a conjugate acid that exists as a gas or a volatile substance.”

  “Wait,” Thorne interjected. “That means we’re looking at anions that form volatile acids when combined with strong acids. Sulfuric acid should work.”

  Valencia tapped her chin in thought. “If we use dilute H2SO4 first, it might let us separate the weaker conjugate acids from the stronger ones.”

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  Cassius nodded. “Yes, sulfuric acid would help us break things down into recognizable reactions. We can divide them into groups: those that react visibly with dilute H2SO4 and those that don’t.”

  “And if we then use concentrated sulfuric acid,” Valencia added, “we can further separate the more stable anions, which would form stronger conjugate acids.”

  Aether turned the pages, scanning quickly. “The notes hint at this too, but they don’t outright state it. That must be the missing step we’re meant to deduce.” He looked up. “This method lets us separate anions systematically. Carbonate, sulfite, sulfide, acetate, and nitrite should react immediately, releasing gases. Chloride, bromide, iodide, nitrate, and oxalate won’t show immediate reactions with dilute acid but might behave differently with concentrated acid.”

  Thorne exhaled. “That means we can get rid of at least half of the vials without needing to check them one by one with a confirmatory test.”

  Cassius straightened up. “Then that’s our plan. First, preliminary acid tests to divide the salts into groups. Then, when we’ve reduced the number of possibilities, we use a confirmatory test on the most likely suspects.”

  Sylvaine Ashford nodded. "This makes sense. Most sulfate salts are insoluble, which means that once we introduce sulfuric acid, the cation won’t interfere. That gives us time to focus solely on identifying the anion."

  A ripple of realization passed through the group. They finally had a structured approach. Instead of blindly testing every vial for chloride, they could now systematically eliminate possibilities.

  "Alright," Cassius said, straightening up. "Let’s divide into teams. Some of us will handle the preliminary sulfuric acid tests, while the rest will organize the remaining notes and determine the next step once we have results."

  The students moved with renewed purpose. The challenge had become a puzzle, and now they had the first piece of the solution. The true test was about to begin.