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Calculate Ph After 5.0 Ml of Naoh

Reviewed by Calculator Editorial Team

This calculator helps determine the resulting pH after adding 5.0 ml of NaOH to a solution. It accounts for the initial solution volume, concentration of NaOH, and initial pH. The calculation follows standard acid-base chemistry principles.

Introduction

When you add sodium hydroxide (NaOH) to a solution, it reacts with water to form hydroxide ions (OH⁻), increasing the solution's alkalinity. The pH of the solution changes based on the amount of NaOH added, the initial pH, and the solution's volume.

This calculator provides a straightforward way to determine the new pH after adding 5.0 ml of NaOH to a solution of known initial pH and volume.

How to Use This Calculator

  1. Enter the initial pH of your solution (must be between 0 and 14).
  2. Input the initial volume of your solution in milliliters (ml).
  3. Enter the concentration of NaOH in molarity (M).
  4. Click "Calculate" to see the resulting pH.
  5. Use the "Reset" button to clear all inputs.

Note

The calculator assumes the solution is at room temperature (25°C) and that the NaOH is fully dissociated.

Formula

pH Calculation Formula

The new pH is calculated using the following steps:

  1. Calculate the moles of OH⁻ added: moles = (volume of NaOH in liters) × (concentration of NaOH in M)
  2. Calculate the initial moles of H₃O⁺: moles = 10^(-initial pH) × (initial volume in liters)
  3. Determine the change in H₃O⁺ concentration: Δ[H₃O⁺] = moles of OH⁻ - moles of H₃O⁺
  4. Calculate the new [H₃O⁺]: [H₃O⁺] = initial [H₃O⁺] + Δ[H₃O⁺]
  5. Convert to pH: pH = -log₁₀([H₃O⁺])

Example Calculation

Suppose you have 100 ml of a solution with an initial pH of 7.0. You add 5.0 ml of 0.1 M NaOH. Here's how to calculate the new pH:

  1. Convert volumes to liters: 5.0 ml = 0.005 L, 100 ml = 0.1 L
  2. Calculate moles of OH⁻: 0.005 L × 0.1 M = 0.0005 moles
  3. Calculate initial moles of H₃O⁺: 10^(-7) × 0.1 L = 0.0000001 moles
  4. Calculate Δ[H₃O⁺]: 0.0005 - 0.0000001 = 0.0004999 moles
  5. Calculate new [H₃O⁺]: 0.0000001 + 0.0004999 = 0.0005 M
  6. Calculate new pH: -log₁₀(0.0005) ≈ 3.30

The resulting pH would be approximately 3.30.

Interpreting Results

The resulting pH value indicates the solution's acidity or alkalinity:

  • pH < 7: Acidic solution
  • pH = 7: Neutral solution
  • pH > 7: Alkaline solution

If the resulting pH is outside the 0-14 range, the calculator will display an error message indicating the input values may be unrealistic.

FAQ

What is the pH scale?

The pH scale measures how acidic or basic a solution is. It ranges from 0 (most acidic) to 14 (most basic), with 7 being neutral.

Why does adding NaOH increase pH?

NaOH dissociates in water to form hydroxide ions (OH⁻), which react with hydrogen ions (H⁺) to form water. This reduces the concentration of H⁺, increasing pH.

What if the resulting pH is outside the 0-14 range?

The calculator will display an error. This typically means the input values are unrealistic for standard laboratory conditions.