Answer:
10.
Explanation:
Hello,
In this case, for the given reaction:
[tex]Cr + Fe(NO_3)_2 \rightarrow Fe + Cr(NO_3)_3[/tex]
By knowing the law of conservation of mass must be respected, the following coefficients do balance the chemical equation:
[tex]2Cr + 3Fe(NO_3)_2 \rightarrow 3Fe + 2Cr(NO_3)_3[/tex]
So the sum of all the coefficients is 10.
Regards.