Consider the reversible reaction,  Fe+3aqYellow+SCN−aqcolourless⇌FeSCN+2aqdeep  redA red colour appears on adding two drops of 0.002 M potassium thiocyanate solution to 1 ml of 0.2 M of Iron(III) nitrate solution due to the formation of FeSCN+2. At equilibrium intensity of red colour remains constant. Intensity of red colour decreases by the addition of (A) H2C2O4aq(B) HgCl2aq(C) KSCNaq