Question

And excess of ag and o3 is there in 200 ml of 0.01 molar solution of dichloro tetra aqua chromium iii chloride

Answer 1

No. of  moles of complex = M (moles/litre) ×V (litre) =0.01 × (100/1000) =0.001

[Cr(H2O)4Cl2]Cl has one ionizable Cl−
10−3 moles of the complex precipitates the same amount of AgCl

That is it would precipitate 0.001 moles of AgCl  

No this is not based on concept of common ion effect  it is simple displacement reaction.
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