Question

A delta is formed at the meeting point of sea water and river water. Why?

Answer 1

Hint: As we have seen that, delta is formed by the meeting of sea water and the river water. There is a reason behind this delta formation. The sea water contains sodium chloride which changes the taste of sea water and this sodium chloride has its own properties.

Complete step by step solution
As we know, rivers contain lots of mud, sand, clay and sea water contains sodium chloride which is an electrolyte. As we know that sand particles are already bigger in size, they settle down quickly when the river meets sea water but the size of clay ranges in colloidal range so the clay are also known as colloidal particles.

When the sea water meets river water, the electrolyte (sodium chloride) when added to the river water containing clay (colloidal particles), the particles of the sol (solid particles in liquid form sol) takes up the ions which are oppositely charged and thus get neutralized. The ion responsible for neutralization of charge on the colloidal particles is called the coagulation ion or flocculating ion. The neutral particles start accumulating to form particles of larger size which settle down as precipitate in the form of delta. Therefore, this is the reason for the formation of delta at the meeting point of sea water and river water.

Note:
When the small concentration of the electrolyte is added, this process is known as flocculation. It can be reversed by shaking.
But when coagulation occurs, the process cannot be reversed simply by shaking.