What is the initial concentration of HOBr if initial solution is .5 liters?

Question

Ti3+ + HOBr <===> TiO2+ + Br¯ (in acid solution)

(a) Write the correctly balanced half-reaction and net ionic equation for the skeletal equation shown above.

Ti3+ + H2O ---> TiO2+ + 2 H+ + e¯

H+ + HOBr + 2e¯ ---> Br¯ + H2O

2 Ti3+ + HOBr + H2O ---> 2 TiO2+ + 3 H+ + Br¯

(b) Identify the oxidizing agent and the reducing agent in this reaction.

HOBr is the oxidizing agent and Ti3+ is the reducing agent.
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My question: The resulting Br- precipitates with silver nitrate. The final precipitate is 2.504 grams. What is the initial concentration of HOBr if initial solution is .5 liters?

Answer 1

Silver Nitrate, AgBr, has a molecular weight of 107.9 + 79.9 = 187.8 g/mol

2.504 g / 187.8 g/mol = 0.01333 mol of AgBr. Since there is only 1 Br atom in each compound, it is also the number of moles of HOBr in the original solution.

0.01333 mol / 0.5 L = 0.00667 M