Domain: Healthcare — Pharmaceutical Chemistry
Target concept: Identification of Chlorpromazine Hydrochloride (Nitric Acid Color Development Method)

Video generation prompt: Place a small amount of chlorpromazine hydrochloride in a clean test tube, add concentrated nitric acid, gently mix, and then subject to gentle heating on a water bath. Demonstrate clear reagent addition, controlled heating, and cautious observation. Emphasize simple and standardized experimental procedures.

Evaluation guide:
(i) Target concept: Visual verification of chlorpromazine hydrochloride identity via nitric acid-mediated oxidative color development, seen as a rapid shift to red that then fades to yellow.
Minimum mechanism: The compound must be present as a solid reactant; concentrated nitric acid must be introduced as a reagent; thermal energy must be applied to help drive the redox reaction; the resulting chromophore must form *only* in solution phase, first appearing red and then gradually fading to yellow; no alternative pathways (e.g., photolysis, hydrolysis, or impurity reactions) permitted, and the color must not remain a stable, unchanging red-brown.
(ii)Storyline: [Frame 1–2] White crystalline solid rests in bottom of upright, transparent test tube. [Frame 3–4] Amber-labeled nitric acid container approaches; liquid flows continuously into tube. [Frame 5–6] Tube is gently agitated (subtle motion, no splashing). [Frame 7–8] Tube is placed into visible water bath; gentle steam or uniform ambient warmth appears. [Frame 9–10] Solution interior transitions uniformly from colorless to red, and then, with continued heating, from red to yellow: no solid discoloration, no tube wall staining, no concurrent bubbling or phase separation. All events occur from fixed frontal view with full test tube in frame; no occlusion of critical interface (solid–acid–solution).

Manual:
Experimental Procedure
1. Place a small amount of white crystalline chlorpromazine hydrochloride in a clean, dry test tube.
2. Add concentrated nitric acid dropwise into the test tube.
3. Gently mix, then place the test tube in a water bath for gentle heating.
Observation of Experimental Phenomena
The solution first turns from colorless to red as the acid is added and the tube is heated; with continued heating/standing, the red color gradually fades to yellow.
Summary of Experimental Principles
Concentrated nitric acid oxidizes the phenothiazine ring system of chlorpromazine hydrochloride, initially producing an unstable red, quinoid-type chromophore; further oxidation converts this red intermediate into a more stable yellow product. This red-to-yellow color sequence — not a persistent red-brown color, and not a nitration (electrophilic substitution) reaction — is the characteristic identification reaction for chlorpromazine hydrochloride.

Prompt Grounding rubric:
level_1: No test tube is visible; no white crystalline solid is shown; no nitric acid container appears; no water bath or other heating setup is shown; none of the actions (placing the solid, adding acid, heating) from the prompt occur.
level_2: A test tube containing a white crystalline solid is shown, but no nitric acid container ever appears and no liquid is added to the tube; or a water bath/heating setup is never shown; or the order of actions is wrong (e.g., the tube appears to be heated before any acid has been added).
level_3: A test tube holding a white crystalline solid is shown; a container of concentrated nitric acid is brought to the test tube and its liquid is poured or dripped into the tube; the tube is then placed into a water bath with visible steam, bubbles, or warm water, consistent with gentle heating; these three steps (solid in tube, acid added, heating) occur in that order.
level_4: Everything in score 3 holds, and additionally: the test tube itself is clean and see-through so its contents stay visible throughout; the nitric acid container is clearly distinguishable as a reagent bottle (e.g., amber/brown glass, a label, or a dropper) rather than an ordinary drinking glass; the water bath is shown with a shallow layer of water and no open flame touching the tube directly; no unrelated props or extra steps are introduced.
level_5: Everything in score 4 holds, and additionally: the solid is already resting in the empty tube before any liquid is added; the acid is poured or dropped directly into the tube without spilling down the outside or hovering indefinitely above it; heating in the water bath begins only once the acid has been fully added and mixed; the water bath stays visible with a steady water level for the whole heating segment; there are no scene cuts, on-screen text, or graphic overlays breaking up the procedure.

Scientific and Causal Correctness rubric:
level_1: The solution never changes color at all and stays colorless/white throughout; or a color appears that has no connection to the acid addition or heating (e.g., it changes before any acid has touched the solid).
level_2: A color change happens, but it is the wrong color for this reaction (e.g., blue, green, or black rather than red); or a color appears immediately on contact before any heating, or appears with no acid having been added at all.
level_3: The solution turns from colorless to a distinctly red color during or shortly after heating begins; this red color is confined to the liquid inside the tube, not the solid or the tube's glass wall; the red color's appearance follows the heating step rather than preceding it.
level_4: Everything in score 3 holds, and additionally: as heating/standing continues, the red color visibly fades and shifts toward yellow rather than staying red-brown indefinitely or darkening toward black; this red-to-yellow change stays confined to the solution, not the tube walls or any solid residue; the change happens gradually over the shown timeframe rather than as an instant jump.
level_5: Everything in score 4 holds, and additionally: the red-to-yellow progression is clearly visible as two distinguishable stages within the clip (an initial red solution, followed by a visibly more yellow solution), not just one static color; the solution's color at each stage looks even throughout the liquid rather than patchy; there is no bubbling, foaming, or cloudy precipitate accompanying the color change; no lighting glare or reflection on the glass could be mistaken for a color the solution doesn't actually have.

Spatiotemporal Consistency rubric:
level_1: The test tube itself is missing from a frame and inexplicably present again later; the solid inside jumps from one spot in the tube to another with no visible cause; liquid appears flowing into the tube from empty space with no acid container in view; the water bath's steam or bubbling switches on and off abruptly between frames with no gradual buildup; or the lighting/shadow shifts abruptly and unrelated to any motion in the scene.
level_2: The test tube stays on screen but suddenly looks a different size or tilts to an unnatural angle between frames; the solid appears already fully dissolved in a frame before the acid has touched it; the nitric acid container disappears from view right after pouring instead of being withdrawn normally; the water bath is visible in one frame and completely absent from the next, then reappears; hand or object motion looks stepped or ghosted rather than continuous.
level_3: The test tube stays in the same place and at the same angle throughout; the solid sits still at the bottom of the tube until the acid reaches it; the acid visibly flows into the tube continuously from the container rather than in disconnected bursts; the water bath stays visibly present and consistent (same water level, same steam/bubble pattern) throughout the heating segment; no object in the scene jumps position, bends unnaturally, or has lighting that switches abruptly between frames.
level_4: Everything in score 3 holds, and additionally: the camera's viewpoint stays fixed with no panning, tilting, or zooming; the test tube is not rocked or rotated beyond a slight, natural wobble while being handled; the liquid's surface inside the tube stays level and rises smoothly as acid is added, without sudden jumps in height; the water bath's steam or bubbling looks steady and continuous rather than surging or suddenly stopping.
level_5: Everything in score 4 holds, and additionally: the nitric acid container stays right next to the test tube for the entire pouring action rather than jumping toward or away from it between frames; no hand or tool blocks the view of both the solid and the liquid surface at the same moment; the water bath stays positioned right alongside the test tube at a constant distance for the whole heating segment; there is no frame-to-frame misalignment, warping, or floating-object appearance suggesting the scene wasn't shot as one continuous take.