Explain: (i) Delta is generally formed when river meets the ocean. (ii) Ferric hydroxide solution is more readily coagulated by Na3PO4 in comparison to KCl

Sediments move downstream in rivers because they are carried by a current of water. Two things happen when the river empties into the sea:
1) suddenly the force of the water current slows down as it enters the sea. With that slowdown, the sediment slows or stops moving, so it is just dumped at the mouth of the river. The ocean currents will start moving some of it along the coast and spread it out, but if the river is carrying much sediment it will overwhelm the ability of the ocean currents to move the sediment away.

2) When "dirty" water in the river (water that has clay particles suspended in it) hits the ocean it mixes with salty sea water. Those clay particles float very well in fresh water, but the salt in sea water causes them to coagulate and stick together and sink to the bottom.


(2)because the relative power of coagulation of fe+3 is much more higher as compared to KCl