pH Formula (Acidic Solution):
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Definition: This calculator determines the pH of a mixture when a strong acid and strong base are mixed and the resulting solution is acidic.
Purpose: It helps chemists and students predict the pH of solutions after acid-base reactions, particularly when the acid is in excess.
The calculator uses the formula:
Where:
Explanation: The formula calculates the excess hydronium ion concentration when acid equivalents exceed base equivalents, then takes the negative logarithm to find pH.
Details: Accurate pH prediction is crucial for chemical reactions, biological systems, industrial processes, and environmental monitoring.
Tips: Enter normality and volume for both acid and base solutions. The calculator only works when acid equivalents exceed base equivalents (resulting in acidic solution).
Q1: When does this formula apply?
A: Only when \( N_1V_1 > N_2V_2 \) (acid is in excess). For basic solutions, a different formula is needed.
Q2: What units should I use?
A: Normality in equivalents per liter (eq/L) and volume in liters (L).
Q3: Can I use molarity instead of normality?
A: For monoprotic acids/bases, yes (normality = molarity). For polyprotic, you must use normality.
Q4: What if I get a negative pH value?
A: This can happen with very concentrated strong acids (pH < 0 is possible but rare).
Q5: How accurate is this calculation?
A: It assumes ideal behavior and complete dissociation. Activity coefficients are not considered.