# When the equation Ni(NO_3)_3 + PbBr_4 -> NiBr_3 + Pb(NO_3)_4 is balanced, what is the coefficient for Ni(NO_3)_3?

Are you sure you can get trivalent nickel? $N i {\left(N {O}_{3}\right)}_{2}$ is more likely.
$\text{Typical oxidation states of nickel are 0, +I, +II, "and rarely} + I V .$