A solution of 4.00 ml of #sf(Sn^(2+))# of unknown concentration is titrated against an acidified solution of 0.495M #sf(Cr_2O_7^(2-)#. The mean titre is 4.94 ml. What is the concentration of the #sf(Sn^(2+))# solution ?
Start with the two 1/2 equations:
To get the electrons to balance we multiply
This tells us that 1 mole of Cr(VI) reacts with 3 moles of Sn(II).