Group 17 Practice Questions

Q1: The interhalogen ICl3 can thermally decompose ICl3  → ICl + Cl2   Is this a redox reaction? Is this a disproportionation?


Q2: Very recently a new element in Group 17 has been discovered, and named Oganesson. It has an atomic number of 118. Predict its physical properties and comment on it predicted reactivity compared to the other halogens.


Q3: A solution is known to contain iodide ions. Chlorine water is added to the solution until no further reaction takes place. A layer of cyclohexane is added above the solution and the aqueous layer and cyclohexane layer shaken together in a separating funnel and allowed to separate. The aqueous layer is then run off and collected. Silver nitrate solution is added to this layer.   Describe fully the observations that could be made during this procedure, and explain what causes each observation.


Q4: A disproportionation reaction takes place between chlorine gas and hot, concentrated sodium hydroxide solution, forming sodium chlorate(v) as one of the products. Several million tons are produced annually for use in bleaching paper. Write a balanced equation for this reaction, and use oxidation numbers to show whether this is disproportionation or not.


Q5:  A solution of an ionic compound X is allowed to react with a solution of silver nitrate. A precipitate is formed, but it is difficult to tell whether it is white or pale cream in colour.

i) Suggest how testing solution X using chlorine water will allow the halide ion present in the solution to be identified.

ii) The halide is found to be bromide.  Write balanced ionic equations with state symbols for the two reactions of X described in this question.