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Chemistry
Acids, Bases and the pH Scale
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REACTION BEAKER · 500 mL
No solution yet
Volume
0 mL
SOLUTION pH
—
Values calculated using the ideal model at 25°C.
H⁺ / OH⁻ balance
No reaction yetInitial amounts before neutralization
H⁺ added0 mol
OH⁻ added0 mol
ReactedExcess
Excess H⁺0 mol
1:1 neutralization ruleH⁺ + OH⁻ → H₂O
Excess OH⁻0 mol
H⁺ and OH⁻ react in a 1:1 molar ratio; other ions stay in solution. The display is relative to support observation and does not show actual ion counts.
HCl
Strong acid in the model
Source remaining: 250 mL
Changing concentration or solution type empties the beaker. Your recorded reference is kept for comparison.
500 mL remaining. Press Pour repeatedly or use Space/Enter.
Tenfold dilution requires solute and a sample of at most 50 mL.
Spacing is for readability; pH values remain logarithmic.
024678101214
Acidic: pH < 7Neutral: pH = 7Basic: pH > 7
A one-unit pH difference corresponds to about ten times in [H⁺] within the model range.
- H⁺ added
- 0 mol
- OH⁻ added
- 0 mol
- [H⁺] equilibrium
- —
- [OH⁻] equilibrium
- —
- pH
- —
- pOH
- —
State: —
Values are computed with the ideal solution model at 25°C.
Universal indicator
0 ≤ pH < 3 · red3 ≤ pH < 5 · orange5 ≤ pH < 6.5 · yellow6.5 ≤ pH < 7.5 · green7.5 ≤ pH < 11.5 · blue11.5 ≤ pH ≤ 14 · purple
No solution yet for the indicator to reflect a pH range.
Model notes
- The model uses monoprotic strong HCl and monobasic strong NaOH in an ideal solution at 25°C.
- The model assumes Kw = 10⁻¹⁴, pH + pOH = 14, additive volumes and H⁺ + OH⁻ → H₂O in a 1:1 molar ratio.
- Near pH 7 the model uses water equilibrium to avoid arithmetic error; pH 7 is only neutral under these 25°C conditions.
- Do not generalize results to weak acids or bases, buffer solutions, polyprotic acids, salt hydrolysis, ion activities, temperature changes, precipitates or gases.
- Indicator colors only estimate a pH range and do not replace a pH meter.
Learning simulation · Ideal strong HCl/NaOH · 25°C · Not a substitute for real laboratory instructions.