When the following skeletal equation is balanced under acidic conditions, what are the coefficients of the species shown?
H3AsO3 + HNO3H3AsO4 + NO
Water appears in the balanced equation as a (reactant, product, neither) with a coefficient of . (Enter 0 for neither.)
Which species is the reducing agent?
To balance the given skeletal equation under acidic conditions and determine the coefficients of the species, we need to follow these steps:
1. Start by balancing the atoms other than hydrogen (H) and oxygen (O). In this case, we only have arsenic (As) and nitrogen (N) to balance.
H3AsO3 + HNO3 -> H3AsO4 + NO
2. Balance the arsenic (As) atoms. There's one on each side, so it is already balanced.
H3AsO3 + HNO3 -> H3AsO4 + NO
3. Balance the nitrogen (N) atoms. In this case, there is only one nitrogen atom on the left side (HNO3) and one on the right side (NO). So, nitrogen is already balanced as well.
H3AsO3 + HNO3 -> H3AsO4 + NO
4. Now, balance the hydrogen (H) atoms by adding hydrogen ions (H+) to the side that needs more hydrogen atoms. In this case, HNO3 needs three hydrogen atoms to match the three on the left side.
H3AsO3 + HNO3 + 3H+ -> H3AsO4 + NO
5. Next, balance the oxygen (O) atoms. The left side has three oxygen atoms from H3AsO3 and three from HNO3 (since nitric acid decomposes). The right side has four oxygen atoms from H3AsO4.
To balance the oxygen atoms, add a water molecule (H2O) for each additional oxygen required on the left side. In this case, we need to add one water molecule.
H3AsO3 + HNO3 + 3H+ -> H3AsO4 + NO + H2O
6. Finally, check if the charges are balanced. The basic idea is that the total positive charge should equal the total negative charge. In this case, it is already balanced.
The balanced equation under acidic conditions is:
H3AsO3 + HNO3 + 3H+ -> H3AsO4 + NO + H2O
Now, let's determine the coefficient for water and identify the reducing agent:
- Water (H2O) appears in the balanced equation as a product with a coefficient of 1.
Therefore, water appears in the balanced equation as a product with a coefficient of 1.
- The reducing agent is the species that undergoes oxidation (loses electrons) in a chemical reaction. In this equation, H3AsO3 is being oxidized to H3AsO4. Therefore, H3AsO3 is the reducing agent.
To balance the skeletal equation, follow these steps:
Step 1: Balance the less common atoms first
In this case, let's start with the arsenic (As) atoms.
H3AsO3 + HNO3 -> H3AsO4 + NO
Step 2: Balance the oxygen (O) atoms by adding water (H2O) as needed
There are 3 oxygen atoms on the left side, and 4 oxygen atoms on the right side. To balance the oxygens, we need to add one molecule of water (H2O) to the left side.
H3AsO3 + HNO3 -> H3AsO4 + NO + H2O
Step 3: Balance the hydrogen (H) atoms
There are 11 hydrogen atoms on the left side and 7 hydrogen atoms on the right side. To balance the hydrogens, we need to add 4 H+ ions to the right side.
H3AsO3 + HNO3 -> H3AsO4 + NO + H2O + 4H+
The coefficients of the species shown in the balanced equation are:
H3AsO3 + HNO3 -> H3AsO4 + NO + H2O + 4H+
Now, let's determine the reducing agent:
In this reaction, the reducing agent is the species that undergoes oxidation, meaning it loses electrons. Since arsenic (As) goes from a lower oxidation state in H3AsO3 to a higher oxidation state in H3AsO4, it is the reducing agent.