balance the following reaction?

Question

HNO_3 + K_2CrO_4 + Fe(NO_3)_2 -> KNO_3 + Cr(NO_3)_3 + Fe(NO_3)_3 + H_2O

Yea I'm normally just fine balancing equations... but this one, not quite! Any help greatly appreciated. Thanks!

this IS the equation. but I guess it's basically impossible.

Answer 1

This is, unfortunately, not the first time I have seen this thing; somebody presented it (with some variation -- it had a ferrocyanide as a reactant, and some oxide of nitrogen as an additional reaction product) a few weeks back, and I spent an hour on it. (Please note that I went to MIT on a chemistry scholarship.) I never did come up with an acceptable answer, some of the coefficients were over 100. So, you need feel no shame at having trouble with it. The following procedure, though tedious, will give you a correct answer: assign variable coefficients a, b, c, d, etc. to each reactant and product, and develop equations for these based on each element in the reaction. Solve all the equations as a linear system, and you'll have it. Keep a box of munchies handy; it will take a while

Answer 2

First, it appears there is a slight discrepancy in the reactant and product charges for Iron Nitrate. If your reactant is Iron (II), which would give you the two molecules of Nitrate, then you should have the same two molecules of Nitrate in the product (instead of three) with Iron (II). Since Iron can be 2+ or 3+, confirm which you have, then fix your equation.