Chloride ions for the salty seawater Where does the chloride ions that are required for the salty taste of sea water come from ?

I know that it is the weathering caused by the slightly acidic (due to dissolution of CO2 with water) rain that dissolves minerals in the water which gets carried to ocean. But the sodium ions/atoms require chloride ions/atoms for the salty taste. But I don't think chloride would be present in the rocks.

Please explain.
Chlorine is a very reactive element. Contrary to your statement, chlorine occurs in many rocks and minerals.

The mineral apatite, with the composition: Ca5(PO4)3(F,Cl,OH), is a natural source of chlorine. Virtually all rocks contain chlorine.

Chlorine even occurs occurs in alkaline magmas. 

One of the most common minerals containing chlorine is common salt, which is sodium chloride, NaCl.

Geologically, chlorine is everywhere. When rocks are exposed to water and acids minerals, including chlorine, dissolve into solution and they are transported to lakes, salt lakes, aquifers and oceans.