6.2 Nilai pH

ASID, BES DAN
GARAM

By Cikgu Azlina Awang

Kertas litmus merah Kertas litmus biru

Bahan beralkali Bahan berasid



ASID NEUTRAL ALKALI



Rumus penentuan nilai pH

pH pOH
pH

- log [H+] - log [OH-]
pH + pOH = 14

pH = 14 - pOH

pH = -log[H+]
pH = -log[0.5]

= -(-0.301)
= 0.301
pH = 0.3

pH = -log[H+]
2.0 = -log[H+]
Log[H+] = -2.0
[H+] = 10-2

= 0.01 mol dm-3
Kemolaran asid hidroklorik = 0.01 mol dm-3

pOH = -log[OH-]
pOH = -log[0.1]

= -(-1)
=1
pOH larutan natrium hidroksida = 1.0

pOH = -log[OH-]
pOH = -log[0.01]

= -(-2)
=2
pOH = 2.0
pH larutan kalium hidroksida= 14.0 - pOH

= 14.0 – 2.0 = 12.0

pH + pOH = 14.0 log[OH-] = -2.0
12.0 + pOH = 14
pOH = 14.0 – 12.0 = 2.0 [OH-] = 10-2
pOH = - log [OH-]
= 0.01 mol dm -3
2.0 = - log[OH-]
Kemolaran larutan litium
hidroksida = 0.01 mol dm-3

Hubungan antara nilai pH dengan
kepekatan H+ dan OH-

Kepekatan ion H+ , nilai pH

Kepekatan ion OH- , nilai pH



Terima kasih
From Cikgu Azlina Awang