pH using logarithmic functions

Question

The pH scale is defined as pH= -log [H⁺], where [H⁺] is the concentration of hydronium ions, measured in mole per litre. 

If pH > 7, the solution is basic.

If pH < 7, the solution is acidic.

Acid rain has a pH between 4 and 5 mol/L.

 

a) If a sample of rainwater has hydrogen ion concentration of 0.000 0017 mol/L, would it be acid rain?

b) What is the range of H⁺ for acid rain? Explain and show your work

Answer 1

pH = -[logH+]

 

H+=0.0000017

 

pH=-(log0.0000017)

 

    =-[log(17)-7]

 

    =7-log(17)

pH<7      is acidic

 

b---

 

Acid rain has pH between 4 & 5

4=-log(H+)

H+=10^(-4)

H+=0.0001

 

5=-log(H+)

H+=10^(-5)

     =0.00001

So, range of H+ =0.00001.   to   0.0001