[candiishop]

Balance the following redox equation using the smallest integers possible and select the correct coefficient for the iron(II) hydroxide, Fe(OH)2.

Fe(OH)2 (s) + CrO4^2- (aq) ---------> Fe2O3(s) + Cr(OH)4- (aq) + H2O (l) + OH-

a) 1
b) 2
c) 3
d) 6

Is the answer 2?

[Borek]

Is the answer 2?

Nope.

[Albert]

candiishop: have you used half reaction to balance the chemical equation?

[candiishop]

Hi.. umm i don't understand what im doing.

So half equations:

Fe(OH)2 ----> Fe2O3
+2                  +3
4Fe(OH2) ----> 2Fe2O3 + 4H20


CrO42- ----> Cr(OH)4-
+6                 +3
CrO42- + 4H+ -----> Cr(OH4)-


Am i on the right track? Thanks

[Borek]

http://www.chembuddy.com/?left=balancing-stoichiometry&right=half-reactions-method

and/or

http://www.chembuddy.com/?left=balancing-stoichiometry&right=oxidation-numbers-method

[candiishop]

q2) When the following redox equation is balanced with smallest whole number coefficients, the coefficient for nitrogen dioxide will be _____ .
I2(s) + HNO3(aq)  HIO3(aq) + NO2(g) + H2O(l)

with this question i work out to be 10 of NO2

I tried answering the other question.. but i don't get how in the products you get OH-?

[Borek]

with this question i work out to be 10 of NO2

Good. I₂ + 10HNO₃ -> 2HIO₃ + 10NO₂ + 4H₂O

I tried answering the other question.. but i don't get how in the products you get OH-?

No idea what you refer to. I guess they were added to help balance oxygen/hydroge/charge. That's a common approach when balanacing redox reactions that take place in alkalic solution. Take a look at the half reaction method page I have mentioned earlier.

[candiishop]

Thanks again for your help