PH Meter MS Body Table Top

Dip the pH Sensor in Chemical Solution to read and display the value. PH Meter MS Body Table Top

What is pH value: PH Meter MS Body Table Top
The pH indicates the Hydrogen ion concentration of any given solution. pH value of a solution signifies the power of hydrogen. To understand the theory of pH, it is important to know about the dissociation property of water. The pH scale has been derived from the dissociation of water. The water dissociates into its H+ and OH- components. The concentration of H+ ion found in pure water 7pH This H+ ion concentration is neither acidic nor alkaline and hence called as neutral.

When the H+ ion concentration is more than 7.0 pH, the solution is acidic; when H+ ion is less than 7.0 pH, then the solution is alkaline. Low pH indicates high H+ ion concentration; High pH indicates low H+ concentration. Hence the pH scale is inversely related to the concentration of H+ in any given solution, and directly related to OH– ion concentration.

pH = -Log10 [H+]

The pH scale is in the range of 1 to 14. When there is a change of pH by unit 1 (for ex. pH changes from 4 to 5), it indicates the change in hydrogen ion concentration by 10 times. When there is a change of pH by 2 units it indicates that the change in hydrogen ion concentration by 100 times. Due to this relationship, the pH scale is called as logarithmic.

pH Value Scale for pH meter.
While we test many experiments, it important to check the pH of any given chemical solution. while the pH checked by pH or litmus paper. The change in litmus paper color indicates the change in pH, it is called as a visual method. For precise noting of pH, an instrument is used and it called a pH meter. The pH meter works on the potentiometric principle.
As the acidic solution has a more positive charge (H+ ion) than the alkaline solution, and the acidic solution has greater potential to produce current than the alkaline solution. The pH meter works to measure the potential difference (voltage) of test solution and standard or known solution and calculates the pH. Hence, it works like a Voltmeter. To complete the circuit, two electrodes connected in order to complete the circuit. The complete circuit allows the movement of electric current.

Working Principle of pH meter:

The working of pH meter is based on the Nernst equation. Nernst equation derives the relation between the electric voltage with ion concentration. The Nernst equation derived for H+ ion concentration is the basis of pH meter. The working principle of pH meter is potentiometry. The pH meter consists of glass (also called an indicator electrode) and a reference electrode. The glass electrode consists of a glass membrane, which is sensitive to the hydrogen ion concentration of test sample solution. And the glass electrode potential varies from sample to sample. The reference electrode is standard and has constant potential. The reference electrode does not respond to test sample solution. The pH meter measures and compares the potential difference between both glass and reference electrodes.

Using the Nernst equation, the potential difference used to measure the hydrogen ion concentration indicating the pH of a given solution. Due to the potential difference between two electrodes, the electron flows and generates a current. This generated current measured by a voltmeter. The relationship between the potential difference generated current and pH has been derived. The potential difference of 1 pH 59.16 mV at 25° C and hence when there is a difference of one pH unit, there will be a change in voltage by 59.16 mV. This relationship employed in measuring the pH.

Construction of pH meter: PH Meter MS Body Table Top

The pH sensor or probe of modern pH meter a combined type, in which test and reference electrodes placed into a glass tube-like structure. The combined electrode consists of the following parts-

pH Meter

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