Question

Highest pH (14) is shown by
1. 0.1 M H₂SO₄
2. 0.1 M NaOH
3. 1 N NaOH
4. 1 N HCl

Answer 1

1. pH = - log [H⁺]

= -log (0.1)
= -log (1 x 10^-1)
= 1 log 10
= 1
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2. pOH = - log [OH^-] ​ = -log (0.1)
= -log (1 x 10^-1)
= 1 log 10
= 1

pH + pOH = 14

pH = 14 - pOH

= 14 -1
= 13
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3. 1 N NaOH = 1 M NaOH

pOH = - log [OH^-] ​ = -log (1)
= 0

pH + pOH = 14

pH = 14 - pOH

= 14 -0
= 14
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4. 1 N HCl = 1 M HCl
pH = - log [H⁺]
​ = -log (1)
= 0
----------------------------------------------------------------------------------------

Thus the answer is 3 (1N NaOH)