Question

Which of these substances has the lowest pH? 0.5 M HBr, pOH = 13.5 0.05 M HCl, pOH = 12.7 0.005 M KOH, pOH = 2.3

Answer 1

Answer;

0.5 M HBr, pOH = 13.5 ; Has the lowest pH

Explanation;

From the question;

pH = -Log [OH]

or pH = 14 - pOH

Therefore;

For 0.5 M HBr

[H+] = 0.5 M

pH = - Log [0.5]

     = 0.30

For;  pOH = 13.5

pH = 14 - pOH

     = 14 -13.5

     = 0.5

For; 0.05 M HCl

pH = - log [H+]

[H+] = 0.05

pH = - Log [0.05]

     = 1.30

For; pOH = 12.7

pH = 14 -pOH

     = 14 -12.7

     = 1.30

For;  0.005 M KOH,

pOH = - log [OH]

[OH-] = 0.005

pOH = - Log 0.005

        = 2.30

pH = 14 - 2.30

     = 11.7

For; pOH = 2.3

   pH = 14 -pOH

         = 14- 2.3

         = 11.7

Answer 2

Answer:

0.5 M HBr, pOH = 13.5

Explanation:

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