Answer
FULL EQUATION: $Cr(OH)_3(s) + 3 HNO_2(aq) → Cr(NO_2)_3(aq) + 3 H_2O(l)$
NET IONIC: $Cr(OH)_3(s) + 3 H+ (aq) → Cr^{3+} (aq) + 3 H_2O(l)$
Work Step by Step
The question involves writing a net ionic equation for the reaction between solid chromium(III) hydroxide and nitrous acid. To start, write down the full balanced molecular equation, converting words into formulas. Note you use double displacement to get H2O and Cr(NO3)3 are formed.
$Cr(OH)_3(s) + 3 HNO_2(aq) → Cr(NO_2)_3(aq) + 3 H_2O(l)$
Now write the full ionic equation (break up strong electrolytes into their ions). Keep water (liquid) and Cr(OH)3 (solid) in their original forms.
Cr(OH)3(s) + 3 H+(aq) + 3 NO2⁻(aq) → Cr3+(aq) + 3 NO2⁻(aq) + 3 H2O(l)
Notice that the nitrate ions (NO2⁻) are present on both sides of the equation and thus are spectator ions. Removing the spectator ions gives us the net ionic equation:
Cr(OH)3(s) + 3 H+ (aq) → Cr3+ (aq) + 3 H2O(l)
