Question

In acidic aqueous solution, the purple complex ion Co(NH3)5Br2+ undergoes a slow reaction in which the bromide ion is replaced by a water molecule, yielding the pinkish-orange complex ion : Co(NH3)5(H2O)3+ Co(NH3)5Br2+Purple(aq)+H2O(l)→ Co(NH3)5(H2O)3+Pinkish−orange(aq)+Br−(aq) The reaction is first order in Co(NH3)5Br2+, the rate constant at 25 ∘C is 6.3×10−6 s−1, and the initial concentration of Co(NH3)5Br2+ is 0.100 M.

What is its molarity after a reaction time of 24.0 h ?

How many hours are required for 77 %% of the Co(NH3)5Br2+Co(NH3)5Br2+ to react

Answer 1

After 24 h, the molarity of [Co(NH3)5Br]2+ is 0.0004 M and for [Co(NH3)5H2O]3+ is 0.0006 M.

For completion of 77%, it will take 64.8 hours.

Explanation: