ACT Science Practice Test 77

I appreciate you sharing this content, but I need to point out a critical issue: **this passage is not text—it's a collection of scientific diagrams, charts, and tables** (a pH scale diagram, lab equipment illustrations, a data table for white phosphorus extraction, and a concentration chart). The instructions I was given are designed to process **OCR'd text passages** from the ACT English test, where underlined phrases appear inline with question markers, and the output wraps those phrases in HTML `` and `_{` tags.

However:
- There is no continuous prose passage here
- There are no underlined text portions to mark
- The questions reference diagrams and numerical data, not sentence-level grammar/style edits
- This appears to be from a **science section** (likely ACT Science), not the **English section**

**I cannot produce valid HTML output** because there's no text structure to process.

If you have an **ACT English passage** (continuous prose with underlined phrases and corresponding questions about grammar, style, or organization), please share that, and I'll gladly render it in the correct HTML format.}

A science class studied the pH strength of acids and bases. The terms strong and weak indicate the ability of acid and base solutions to conduct electricity. Figure 1 displays the pH scale used to rank solutions as acidic or basic, and Table 1 provides an overview of what pH levels are considered strong and weak solutions.

Figure 1

Table 1

Solution	pH
Strong acid	0–3
Weak acid	4–6
Neutral	7
Weak base	8–10
Strong base	11–14

Experiment 1

Students conducted an experiment to determine the conductivity of acid and base solutions, using a light bulb apparatus (see Figure 2). The light bulb circuit was incomplete. If the circuit is completed by a solution containing a large number of ions, the light bulb will glow brightly, indicating a strong ability to conduct electricity. If the circuit is completed by a solution containing a large number of molecules and either no ions or few ions, the solution does not conduct electricity or conducts it very weakly. Students tested the conductivity of several solutions; the results are reported in Table 2.

Figure 2

Table 2

Solution	Acid or Base	Light Bulb
H₂O	Neutral	No light
HCl	Acid	Bright
HC₂H3O₂	Acid	Dim
H₂SO₄	Acid	Bright
H₂CO₃	Acid	Dim
NaOH	Base	Bright
KOH	Base	Bright
NH₄OH	Base	Dim

Experiment 2

Students mixed 50 mL of each chemical with 1 liter of water and then tested the pH of the solution. Table 3 displays the pH found for each chemical.

Table 3

Chemical	pH
HCL	0.86
HC₂H3O₂	2.92
H₂SO₄	1.29
H₂CO₃	3.73
NaOH	13.1
KOH	11.2
NH₄OH	9.2

Solid-phase microextraction (SPME) is a new technique for extracting volatile organic residue from sediment and water. The technique has several advantages (fast, simple, precise, sensitive), and requires no solvent. For this technique, a thin fused silica fiber coated with a stationary phase is exposed to a sample, either by immersion in a water or air sample or to headspace above an aqueous or solid sample (see Figure 1).

Figure 1: SPME device

Scientists conducted a series of experiments to determine the effectiveness of using SPME to extract white phosphorus (P₄) residues from water. All of the experiments were done using headspace immersion.

Experiment 1

To see how consistent SPME was, scientists conducted five trials using four different types of water (reagent grade, well, pond, salt marsh) at an aqueous concentration of 0.14 μg/L. Table 1 displays the results.

Table 1

Experiment 2

Scientists varied the aqueous concentration and tested four different types of water using SPME, to see the effect on the mass of P₄ that could be extracted (see Figure 2).

Figure 2

Experiment 3

To see if sonication had any effect on the results of SPME, scientists ran four trials, using four identical aqueous samples, at a concentration of 0.14 μg/L. The samples were analyzed using SPME by three methods: five minutes of sonication, ten minutes of sonication, and five minutes static. Table 2 displays the results.

Table 2

Science practice 56