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Calculate Ph of 0.1m Naoh

Reviewed by Calculator Editorial Team

This calculator helps you determine the pH of a 0.1 molar (0.1M) sodium hydroxide (NaOH) solution. Sodium hydroxide is a strong base that completely dissociates in water, making it ideal for pH calculations. Understanding the pH of NaOH solutions is essential in chemistry, biology, and environmental science.

How to Calculate pH of 0.1M NaOH

Calculating the pH of a 0.1M NaOH solution involves understanding the relationship between concentration and pH for strong bases. Here's a step-by-step guide:

Step 1: Understand the Dissociation of NaOH

NaOH is a strong base that completely dissociates in water according to the equation:

Dissociation Equation

NaOH → Na⁺ + OH⁻

Step 2: Calculate the Hydroxide Ion Concentration

For a 0.1M NaOH solution, the concentration of hydroxide ions (OH⁻) is equal to the concentration of NaOH because it fully dissociates:

OH⁻ Concentration

[OH⁻] = [NaOH] = 0.1 M

Step 3: Use the pOH Formula

The pOH is calculated using the formula:

pOH Formula

pOH = -log[OH⁻]

Step 4: Convert pOH to pH

Since pH and pOH are related by the equation:

pH and pOH Relationship

pH + pOH = 14

You can calculate the pH by subtracting pOH from 14.

Step 5: Perform the Calculation

For a 0.1M NaOH solution:

  1. Calculate pOH: pOH = -log(0.1) = 1
  2. Calculate pH: pH = 14 - pOH = 14 - 1 = 13

The pH of a 0.1M NaOH solution is 13.

pH Calculation Formula

The pH of a strong base solution can be calculated using the following steps:

Step-by-Step Formula

  1. Determine the concentration of hydroxide ions: [OH⁻] = [Base]
  2. Calculate pOH: pOH = -log[OH⁻]
  3. Calculate pH: pH = 14 - pOH

For a 0.1M NaOH solution:

Calculation Example

[OH⁻] = 0.1 M

pOH = -log(0.1) = 1

pH = 14 - 1 = 13

Important Notes

  • This formula applies only to strong bases that fully dissociate in water.
  • The pH of a strong base solution is always greater than 7.
  • For weak bases, additional calculations are required to account for partial dissociation.

Worked Example

Let's calculate the pH of a 0.1M NaOH solution using the steps above.

Given:

  • Concentration of NaOH = 0.1 M

Step 1: Determine [OH⁻]

Since NaOH is a strong base, [OH⁻] = [NaOH] = 0.1 M.

Step 2: Calculate pOH

pOH = -log[OH⁻] = -log(0.1) = 1

Step 3: Calculate pH

pH = 14 - pOH = 14 - 1 = 13

Result:

The pH of a 0.1M NaOH solution is 13.

Verification

To verify this result, you can use our calculator in the sidebar or any standard pH calculation tool. The result should consistently show pH = 13 for a 0.1M NaOH solution.

FAQ

What is the pH of a 0.1M NaOH solution?

The pH of a 0.1M NaOH solution is 13. This is calculated by determining the hydroxide ion concentration, converting it to pOH, and then converting pOH to pH.

Why is the pH of a strong base solution greater than 7?

The pH scale ranges from 0 to 14, with values below 7 indicating acidity and values above 7 indicating alkalinity. Strong bases like NaOH release hydroxide ions (OH⁻) into solution, increasing the pH above 7.

Can this formula be used for weak bases?

No, this formula is specific to strong bases that fully dissociate in water. For weak bases, additional calculations are needed to account for partial dissociation and the equilibrium constant (Kb).

What happens if the concentration of NaOH changes?

The pH of the solution will change proportionally. For example, a 0.01M NaOH solution would have a pH of 12, while a 1M NaOH solution would have a pH of 14. The relationship between concentration and pH is logarithmic.