Question

Assign oxidation numbers to each element in (a) nitrogen oxide (b) ammonia (c) potassium peroxide (d) chlorate ion \(\left(\mathrm{ClO}_{3}^{-}\right)\)

Short answer

Question: Determine the oxidation numbers of each element in the following compounds: a) nitrogen oxide (NO), b) ammonia (NH3), c) potassium peroxide (K2O2), d) chlorate ion (ClO3-). Answer: a) In nitrogen oxide (NO), the oxidation numbers for nitrogen and oxygen are +2 and -2, respectively. b) In ammonia (NH3), the oxidation numbers for nitrogen and hydrogen are -3 and +1, respectively. c) In potassium peroxide (K2O2), the oxidation numbers for potassium and oxygen are +1 and -1, respectively. d) In the chlorate ion (ClO3-), the oxidation numbers for chlorine and oxygen are +5 and -2, respectively.

Step-by-step solution

Understand oxidation number rules

In order to assign oxidation numbers to each element, we need to know the following rules: 1. The oxidation number of an atom in its elemental state is always 0. 2. The oxidation number of a monatomic ion is equal to its charge. 3. The oxidation numbers of all atoms in a polyatomic ion must add up to the overall charge of the ion. 4. In compounds, the oxidation number of hydrogen and oxygen are generally +1 and -2, respectively.

Assign oxidation numbers to nitrogen oxide (NO)

Oxygen has an oxidation number of -2. Let's denote the oxidation number of nitrogen as x. Since there is no overall charge on the molecule, we can write an equation: x - 2 = 0 Solving for x, we get x = 2. So, the oxidation numbers for nitrogen and oxygen in NO are +2 and -2, respectively.

Assign oxidation numbers to ammonia (NH3)

Hydrogen has an oxidation number of +1. There are 3 hydrogen atoms in ammonia. Let's denote the oxidation number of nitrogen as y. Since there is no overall charge on the molecule, we can write an equation: y + 3(1) = 0 Solving for y, we get y = -3. So, the oxidation numbers for nitrogen and hydrogen in NH3 are -3 and +1, respectively.

Assign oxidation numbers to potassium peroxide (K2O2)

Potassium is a monatomic ion with a charge of +1. In peroxides, oxygen has an oxidation number of -1 (an exception to rule 4). There are 2 potassium and 2 oxygen atoms in K2O2. Let's write an equation based on their charges and the fact that there is no overall charge on the molecule: 2(+1) + 2(-1) = 0 Since the equation is already balanced, we don't need to solve for any unknown variable. So, the oxidation numbers for potassium and oxygen in K2O2 are +1 and -1, respectively.

Assign oxidation numbers to chlorate ion (ClO3-)

Oxygen has an oxidation number of -2. There are 3 oxygen atoms in ClO3-. Let's denote the oxidation number of chlorine as z. Since the overall charge of the ion is -1, we can write an equation: z + 3(-2) = -1 Simplifying, we get z - 6 = -1 Solving for z, we get z = 5. So, the oxidation numbers for chlorine and oxygen in ClO3- are +5 and -2, respectively.