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)+B r?(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.

A; What is its molarity after a reaction time of 19.0h ?

B; How many hours are required for 69% of the Co(NH3)5Br2+ to react?

A) 0.065 M is its molarity after a reaction time of 19.0 hour.

B) In 52 hours will react 69% of its initial concentration.

Explanation:

The reaction is first order in :

Initial concentration of =

a) Final concentration of after 19.0 hours=

t = 19.0 hour = 19.0 × 3600 seconds ( 1 hour = 3600 seconds)

Rate constant of the reaction = k =

The integrated law of first order kinetic is given as:

0.065 M is its molarity after a reaction time of 19.0 h.

b)

Initial concentration of =

Final concentration of after t =

Rate constant of the reaction = k =

The integrated law of first order kinetic is given as:

t = 185,902.06 s = ≈ 52 hours

In 52 hours will react 69% of its initial concentration.

fe 55.85 g/mol and h2o 18.02 g/mol.