To find the activity of bromide ions in a water sample, an anion-sensitive electrode is used. The following are the conditions/materials used/gathered from the experiment:

• Standard solution contained 0.0045 M KBr
• Measured potential was (+)77.5 mV against an SCE
• The same electrode was used again and measured a potential of 53.7 mV against an SCE
• Assuming bromide ion size parameter is 4 Angstrom; amu(Br-) = 79.904 g/mol ; ionic strength uKBr = 0.005

1. What is the activity and concentration (mmol/L) of the bromide ions in the water sample?
2. Is the concentration within the WHO recommended limit for drinking water? (Less than 0.075 mmol Br-/L (6mg/L) for adults)