Question

Write a balanced half-reaction for the reduction of aqueous nitrous acid hno2 to gaseous nitric oxide no in basic aqueous solution. be sure to add physical state symbols where appropriate.

Answer 1

The unbalanced chemical reaction of the transformation of aqueous nitrous acid to gaseous nitric oxide is as follows:

HNO₂ (aq) → NO (g)

In the above-mentioned equation, balancing is done by adding a OH,

HNO₂ (aq) → NO (g) + OH⁻ (aq)

Now, the balancing of the charge is done by adding the electrons on the left side,

HNO₂ (aq) + e⁻ → NO (g) + OH⁻ (aq)

Therefore, the balanced half-reaction in the basic medium is as follows:

HNO₂ (aq) + e⁻ = NO (g) + OH⁻ (aq)

Answer 2

Unbalanced half reaction: 

NO(g) ---> HNO2(aq) 

work out to balance the oxygen: 

NO(g) + H2O(l) ---> HNO2(aq) 

balance the Hydrogen (like that in acidic solution): 

NO(g) + H2O(l) ---> HNO2(aq) + H^+ 

balance for charge: 

NO(g) + H2O(l) ---> HNO2(aq) + H^+ + e- 

Change into basic solution: 

OH^-(aq) + NO(g) + H2O(l) ---> HNO2(aq) + H2O(l) + e- 

Drop  water: 

OH^-(aq) + NO(g ---> HNO2(aq) + e-