9 Facts on Ph Of Bleach: Types, Factors And Reasons

What is the pH of Bleach?

The pH of bleach depends on the type of bleach and its concentration. Substantially, the pH of most common sodium hypochlorite bleach ranges between 12 and 13, showing that it is a strong base. 

What is the pH of different types of Bleach?

The pH of bleach depends on its chemical composition. Here pH ranges for some common bleach are listed below:

Type of BleachpH Value
Sodium hypochlorite bleach12 to 13
Enzyme bleach7 to 8
Percarbonate of soda bleach7 to 10
Natural bleachVariable (depending on the ingredients used)

Why is pH different for different types of Bleach?

The pH is different for different types of bleach depending on their active ingredients. For example, 

  • Chlorine bleach has a pH of 12 to 13. It is because the active ingredient in chlorine bleach is sodium hypochlorite which is a strong alkali. 
  • In contrast, oxygen bleach has a pH of 10 to 11. It is because the active ingredient in oxygen bleach is hydrogen peroxide, which is a weakly acidic compound.

How does pH affect the cleaning ability of Bleach?

The pH affects the cleaning ability and stability of Bleach. At lower pH values, bleach rapidly breaks down into salt and water. Thus, its cleaning ability is reduced. Further, the pH of the solution being cleaned also alters the cleaning ability of bleach. Bleach is most effective at a pH of 8 to 10.

What is the significance of knowing Bleach’s pH?

Knowing the pH of bleach is vital for its safety and effectiveness. It helps users understand how to use bleach properly and avoid potential hazards. For example, a high-pH bleach can corrode metal surfaces and damage fabrics. It can also lead to eye and respiratory irritation if the fumes are inhaled.

How can we determine the pH of Bleach?

We can determine the pH of bleach by utilising the following methods:

  • pH test strips
  • pH meter

Factors Affecting the pH of Bleach

There are various factors that affect the pH of bleach. A few of them are as follows:

  1. The concentration of bleach: Bleach pH is directly related to its concentration. The higher the concentrations of bleach lower would be its pH value.
  2. Temperature: The pH of bleach can be influenced by temperature variation. For example, heating bleach makes it more alkaline, and its pH value increases.
  3. Exposure to air: Bleach reacts with the air leading to a change in pH value.
  4. Exposure to light: Bleach pH can also be altered by light exposure.
  5. Contact with other chemicals: Bleach’s pH can be influenced by its contact with other chemicals. 
  6. Age of bleach: Over time, as it ages, the pH of bleach changes. It is because the active ingredient, sodium hypochlorite, breaks down, which changes the pH.

About the author

I am Leena Raswant, a chemistry postgraduate. I thrive on challenges and continually specified goals. I aim to learn, unlearn, relearn and spread my knowledge in the best possible ways.

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