A typical pH value for rain or snow in the northeastern United States is about 4.0.

Question

s this basic or acidic? What is the corresponding hydrogen concentration? How does this compare with the hydrogen concentration of pure water?

Round your answers to two decimal places when necessary.

 

1.) [H⁺] of rain: ______ x 10^-5

2.) [H⁺] of pure water: ______ x 10^-7

Answer 1

pH = 4.0 < 7 ⇒ acidic

 

pH = -log[H₃O⁺]

 

[H₃O⁺] = 10^-pH = 10^-4.0 = 1.0 x 10^-4 = 10 x 10^-5

 

Pure water is neutral ⇒ pH = 7

 

[H₃O⁺] = 10^-7 = 1 x 10^-7