Electrical Conductivity (EC) and Total Dissolved Solids (TDS)

Introduction:
Electrical conductivity (EC) is a measure of a solution's ability to conduct an electric current. It is the measure of the concentration of ionic species present in the solution. Total Dissolved Solids (TDS) refers to the amount of inorganic and organic substances dissolved in water. These substances can include minerals, salts, metals, and other compounds.

Interrelationship between EC and TDS:
The electrical conductivity of water is directly related to the total dissolved solids present in the water. As the concentration of dissolved solids increases, the electrical conductivity also increases. This relationship can be explained by the presence of charged ions in the water.

Explanation:
When dissolved solids, such as salts and minerals, are present in water, they dissociate into charged ions. These ions are responsible for the electrical conductivity of the water. The more ions present in the water, the higher its conductivity.

Effect of TDS on EC:
As the concentration of dissolved solids (TDS) increases in water, the number of ions also increases. This increase in ions enhances the conductivity of water, resulting in an increase in electrical conductivity (EC). Therefore, the correct answer is option 'B' - the EC increases with an increase in TDS.

Factors affecting the relationship between EC and TDS:
It is important to note that the relationship between EC and TDS is not a direct one-to-one correlation. Several factors can affect this relationship:

1. Ion mobility: The mobility of ions in the solution can vary, depending on their size and charge. Some ions may have higher mobility than others, affecting the overall electrical conductivity.

2. Temperature: The temperature of the water can also influence the relationship between EC and TDS. As the temperature increases, the mobility of ions increases, leading to a higher EC.

3. Presence of non-ionic substances: TDS includes both ionic and non-ionic substances. Non-ionic substances, such as organic compounds, do not contribute to the electrical conductivity. Therefore, the relationship between EC and TDS may be influenced by the proportion of non-ionic substances present in the water.

Conclusion:
In conclusion, the electrical conductivity (EC) of water is directly related to the total dissolved solids (TDS) present in the water. As the concentration of dissolved solids increases, the EC also increases. This relationship is influenced by factors such as ion mobility, temperature, and the presence of non-ionic substances.