Question

Write the chemical formula for each of the following compounds, and indicate the oxidation state of the halogen or noble-gas atom in each: (a) chlorate ion, (b) hydroiodic acid, (c) iodine trichloride, (d) sodium hypochlorite, (e) perchloric acid, (f) xenon tetrafluoride.

Short answer

(a) Chlorate ion: \(ClO_3^-\), oxidation state of chlorine is +5. (b) Hydroiodic acid: HI, oxidation state of iodine is -1. (c) Iodine trichloride: ICl3, oxidation state of iodine is +3. (d) Sodium hypochlorite: NaClO, oxidation state of chlorine is +1. (e) Perchloric acid: HClO4, oxidation state of chlorine is +7. (f) Xenon tetrafluoride: XeF4, oxidation state of xenon is +4.

Step-by-step solution

(a) Chlorate Ion

The chlorate ion is a polyatomic ion with the chemical formula \(ClO_3^-\). To determine the oxidation state of the chlorine atom, we create an algebraic equation: Let the oxidation state of chlorine be x. We know that the sum of the oxidation states of all the atoms in the ion should equal the net charge of the ion: x + 3(-2) = -1 x - 6 = -1 x = +5 The oxidation state of chlorine in the chlorate ion is +5.

(b) Hydroiodic Acid

The chemical formula for hydroiodic acid is HI. The oxidation state of iodine (I) in HI is -1 since hydrogen has an oxidation state of +1.

(c) Iodine Trichloride

The chemical formula for iodine trichloride is ICl3. Let the oxidation state of iodine be x. The sum of the oxidation states of all the atoms should equal the overall molecular charge, which is 0. x + 3(-1) = 0 x - 3 = 0 x = +3 The oxidation state of iodine in iodine trichloride is +3.

(d) Sodium Hypochlorite

The chemical formula for sodium hypochlorite is NaClO. The oxidation state of chlorine in the compound is as follows: Let the oxidation state of chlorine be x. Sodium has an oxidation state of +1 and oxygen has an oxidation state of -2. +1 + x -2 = 0 x -1 = 0 x = +1 The oxidation state of chlorine in sodium hypochlorite is +1.

(e) Perchloric Acid

The chemical formula for perchloric acid is HClO4. To find the oxidation state of chlorine we set up an algebraic equation again: Let the oxidation state of chlorine be x. Hydrogen has an oxidation state of +1, and there are 4 oxygen atoms, each with an oxidation state of -2. +1 + x + 4(-2) = 0 x -7 = 0 x = +7 The oxidation state of chlorine in perchloric acid is +7.

(f) Xenon Tetrafluoride

The chemical formula for xenon tetrafluoride is XeF4. To find the oxidation state of xenon (Xe), we know that the sum of oxidation states of all the atoms should equal the overall molecular charge, which is 0. Let the oxidation state of xenon be x. Fluorine has an oxidation state of -1. x + 4(-1) = 0 x - 4 = 0 x = +4 The oxidation state of xenon in xenon tetrafluoride is +4. In summary: (a) Chlorate Ion (chlorine): \(ClO_3^-\), +5 (b) Hydroiodic Acid (iodine): HI, -1 (c) Iodine Trichloride (iodine): ICl3, +3 (d) Sodium Hypochlorite (chlorine): NaClO, +1 (e) Perchloric Acid (chlorine): HClO4, +7 (f) Xenon Tetrafluoride (xenon): XeF4, +4