pH Calculator

pH Calculator 

Find the pH and the related values for any solution using the pH calculator. It can find four values pH, pOH, H+, and OH-. It also tells how the values were computed.

What is pH scale?

The pH scale is a logarithmic scale used to specify the acidity or basicity (alkalinity) of an aqueous solution. The scale ranges from 0 to 14.

• Acidic solutions have a pH less than 7. The lower the pH, the more acidic the solution.
• Basic or alkaline solutions have a pH greater than 7. The higher the pH, the more basic the solution.
• A pH of 7 is considered neutral, meaning it is neither acidic nor basic. Pure water is typically considered to be neutral, with a pH of 7.

Acids increase the hydrogen ion concentration in a solution, while bases decrease it by generating hydroxide ions (OH−) that combine with hydrogen ions to produce water. 

The relationships between pH, pOH, H+, and OH- in an aqueous solution can be described using several formulas:

Finding pH and pOH

1. pH:

pH = −log10([H+])

Where [H+] is the concentration of hydrogen ions in the solution, measured in moles per liter (M).

2. pOH:

pOH = −log10 ([OH−])

Where [OH−] is the concentration of hydroxide ions in the solution, also measured in moles per liter (M).

Relationship between pH and pOH

At 25°C (298K), the sum of the pH and the pOH of a solution is always 14, due to the ion product of water (Kw):

pH + pOH = 14

Finding H+ and OH−

1. To find the hydrogen ion concentration ([H +]) from the pH:

[H+] = 10^-pH 

2. To find the hydroxide ion concentration ([OH−]) from the pOH:

[OH−] = 10^−pOH 

Additional Note:

The ion product constant of water (kw) describes the relationship between 

[H+] and [OH−] at a particular temperature. At 25°C, it is:

Kw = [H+] × [OH−] = 1.0×10^−14

Applications of pH:

The pH scale is incredibly important across a variety of fields due to its ability to quantify the acidity or alkalinity of a solution. Here are some key areas where the pH scale is utilized:

1. Chemistry

• Research and Experimentation: pH is crucial in chemical research and experiments to ensure reactions occur under desired conditions.
• Buffer Solutions: Understanding and controlling pH is essential for creating buffer solutions that maintain a consistent pH level.

2. Biology and Medicine

• Body pH: The pH of bodily fluids, such as blood (around pH 7.4), is crucial for maintaining life and is therefore carefully regulated.
• Drug Development: Developing drugs and other treatments often requires pH measurement to ensure the correct conditions for stability and function.

3. Agriculture

• Soil pH: Soil pH affects the availability of nutrients to plants, and thus, it's essential to monitor and sometimes adjust it to optimize plant growth.
• Fertilizers: The pH of fertilizers is considered to ensure they don't adversely affect soil pH and, consequently, plant health.