Mr Johar gives daisy two solutions. He tells her to choose the best indicator to find out which solution is pH 4 and which is pH 6. Write down which indicator daisy should use. Explain your answer.

The amount of iron in ore can be quantitatively determined by titrating a solution of the unknown with a standard solution of dichromate, cr2o72−. the net ionic equation is 6fe2+(aq)+cr2o72−(aq)+14h+(aq)→6fe3+(aq)+2cr3+(aq)+7h2o(aq) part a the titration of 25.0 ml of an iron(ii) solution required 18.0 ml of a 0.230 m solution of dichromate to reach the equivalence point. what is the molarity of the iron(ii) solution?