Use the shortcut rules to assign an oxidation state to each atom in:
a) PCI3
b) H2S
c) MnO4-
d) HNO3
e) HCOOH
f) S2O32-
To assign oxidation states using the shortcut rules, follow these steps:
Step 1: Identify the elements in the compound.
Step 2: Determine the oxidation state of more electronegative elements first.
Step 3: Allocate the remaining oxidation states based on the overall charge of the compound, assuming all bonds are ionic.
Let's go through each compound:
a) PCI3
- Phosphorus (P) is less electronegative than Chlorine (Cl), so Chlorine's oxidation state will be -1.
- Since there are three chlorine atoms in PCI3, their total oxidation state is -3.
- The overall charge of PCI3 is 0, and since the sum of the oxidation states should be equal to the overall charge, the oxidation state of Phosphorus (P) will be +3.
b) H2S
- Hydrogen (H) is less electronegative than Sulfur (S), so Hydrogen's oxidation state will be +1.
- Since there are two hydrogen atoms in H2S, their total oxidation state is +2.
- The overall charge of H2S is 0, and since the sum of the oxidation states should be equal to the overall charge, the oxidation state of Sulfur (S) will be -2.
c) MnO4-
- Oxygen (O) usually has an oxidation state of -2.
- There are four oxygen atoms in MnO4-, so their total oxidation state is -8.
- The overall charge of MnO4- is -1, and since the sum of the oxidation states should be equal to the overall charge, the oxidation state of Manganese (Mn) will be +7.
d) HNO3
- Hydrogen (H) is less electronegative than Nitrogen (N), so Hydrogen's oxidation state will be +1.
- Oxygen (O) usually has an oxidation state of -2.
- There are three oxygen atoms in HNO3, so their total oxidation state is -6.
- The overall charge of HNO3 is 0, and since the sum of the oxidation states should be equal to the overall charge, the oxidation state of Nitrogen (N) will be +5.
e) HCOOH
- Hydrogen (H) is less electronegative than Carbon (C), so Hydrogen's oxidation state will be +1.
- Oxygen (O) usually has an oxidation state of -2.
- There are two oxygen atoms in HCOOH, so their total oxidation state is -4.
- The overall charge of HCOOH is 0, and since the sum of the oxidation states should be equal to the overall charge, the oxidation state of Carbon (C) will be +2.
f) S2O32-
- Oxygen (O) usually has an oxidation state of -2.
- There are three oxygen atoms in S2O32-, so their total oxidation state is -6.
- The overall charge of S2O32- is -2, and since the sum of the oxidation states should be equal to the overall charge, the oxidation state of Sulfur (S) is +4. Since there are two sulfur atoms, each will have an oxidation state of +2.
Remember, these are just general rules and there may be exceptions in more complex compounds.