Solid sodium chloride reacts with concentrated sulfuric acid to produce hydrogen chloride gas.

1. Write a balanced chemical equation for this reaction.
2. State the role of the sulfuric acid in this reaction.

A yellow solid and purple fumes are formed when solid potassium iodide reacts with concentrated sulfuric acid.

1. Write a balanced equation for the reaction of iodide ions with sulfuric acid that produces the yellow solid.
2. State the role of the sulfuric acid in this reaction.

Chlorine reacts with cold, dilute aqueous sodium hydroxide as shown in the equation: ${Cl}_2+2NaOH\to NaClO+NaCl+H_{2}O$

1. Determine the oxidation state of chlorine in $NaClO$ and in $NaCl$.
2. State, in terms of redox, what happens to chlorine in this reaction.

Solution X contains two different negative ions. To a sample of solution X in a test tube, a student adds:

• silver nitrate solution
• then an excess of dilute nitric acid
• finally an excess of dilute ammonia solution.

The observations after each addition are recorded in the table below:

1. Give the formulas of D, E, and F.
2. Give an ionic equation to show the formation of E.
3. Give an equation to show the conversion of D into G.