MCQ Detailed View

Seawater contains a variety of dissolved salts, minerals, and ions, giving it a distinct salinity. The average salinity of seawater is about 3.5%, meaning that in every 1 liter of seawater, there are approximately 35 grams of dissolved salts. The majority of these salts are sodium chloride (NaCl), but seawater also contains magnesium, calcium, potassium, and sulfate ions in smaller amounts.

Salinity varies slightly depending on location, temperature, and evaporation rates. For example, in areas with high evaporation and low freshwater input, such as the Red Sea, salinity may exceed 4%. In polar regions, where melting ice adds fresh water, salinity can be lower than the average.

Understanding salinity is important in physical chemistry, environmental science, and oceanography. Salinity affects the density and freezing point of seawater. Higher salinity increases water density, influencing ocean currents and climate. It also impacts marine life because different species are adapted to specific salinity ranges.

Seawater salinity is measured using methods such as evaporation and weighing, conductivity, or refractometry. Accurate knowledge of salinity is essential for oceanography, marine engineering, and desalination processes. Salinity also plays a role in chemical reactions in water, such as precipitation and ionic interactions.

The average value of 3.5% is a standard reference used in scientific studies, textbooks, and environmental assessments. It reflects the balance between dissolved salts from rivers, underwater volcanic activity, and mineral inputs with the removal processes like precipitation and biological uptake.