In: Chemistry

Calculate the pH of a 0.0204 M KOH solution at each temperature.

For 15 (4.57 ×
10^{–15
}15
°C
pH=

For 45 (3.94 × 10^{–14}) 45 °C pH=

Sol :-

**(a)**. **At 15 ^{0}C
:-**

Given ,

[KOH] = [OH^{-}] = 0.0204 M

It is given that , Ionic product of water (K_{w}) at 15
^{0}C = 4.57 x 10^{-15}

Also,

K_{w} = [H^{+}].[OH^{-}]

4.57 x 10^{-15} M^{2} = [H^{+}] x 0.0204
M

[H^{+}] = 4.57 x 10^{-15} M^{2} / 0.0204
M

[H^{+}] = 2.24 x 10^{-13} M

Also,

pH = - log [H^{+}]

So,

pH = - log 2.24 x 10^{-13} M

pH = 12.65

Hence, pH of 0.0204 M KOH at 15^{0}C =
12.65 |

-------------------------

**(b)**. **At 45 ^{0}C
:-**

Given ,

[KOH] = [OH^{-}] = 0.0204 M

It is given that , Ionic product of water (K_{w}) at 45
^{0}C = 3.94 x 10^{-14}

Also,

K_{w} = [H^{+}].[OH^{-}]

3.94 x 10^{-14} M^{2} = [H^{+}] x
0.0204 M

[H^{+}] = 3.94 x
10^{-14} M^{2} / 0.0204 M

[H^{+}] = 1.93 x 10^{-12} M

Also,

pH = - log [H^{+}]

So,

pH = - log 1.93 x 10^{-12} M

pH = 11.71

Hence, pH of 0.0204 M KOH at 45^{0}C =
11.71 |

-------------------------

pH and Activity
Calculate the pH of a solution which is 0.0010 M in KOH and 0.013 M
in NaNO3 using activities.
Calculate a pH for the same solution, ignoring
activities

1. Calculate the pH of a 0.76 M KOH solution.
pH
2.
Be sure to answer all parts.
Calculate the pOH and pH of the following aqueous solutions at 25
°
C:
(a) 0.0715 M LiOH
pH =
pOH =
(b) 0.0521 M Ba(OH)2
pH =
pOH =
(c) 0.12 M NaOH
pH =
pOH =

A 25.0−mL solution of 0.100 M CH3COOH is titrated with a 0.200 M
KOH solution. Calculate the pH after the following additions of the
KOH solution
(a) 10.0 mL
(b) 12.5 mL
(c) 15.0 mL

A 26.0−mL solution of 0.120 M CH3COOH is titrated with a 0.220 M
KOH solution. Calculate the pH after the following additions of the
KOH solution:
(a) 0.00 mL
(b) 5.00 mL

1. Calculate the pH of a solution that results from mixing 15 mL
of 0.13 M HBrO(aq) with 11 mL of 0.1 M NaBrO(aq). The Ka
value for HBrO is 2 x 10-9.
2. What is the buffer component ratio, (BrO-)/(HBrO)
of a bromate buffer that has a pH of 7.91. Ka of HBrO is
2.3 x 10-9.

Calculate the pH of each solution.
A. A solution containing 0.0133 M maleic acid and 0.0189 M
disodium maleate. The Ka values for maleic acid are 1.20×10−2 (Ka1)
and 5.37×10−7 (Ka2).
B. A solution containing 0.0368 M succinic acid and 0.022 M
potassium hydrogen succinate. The Ka values for succinic acid are
6.21×10−5 (Ka1) and 2.31×10−6 (Ka2).

Calculate the pH during the titration of 30.00 mL of 0.1000
M KOH with 0.1000 M HBr solution after the
following additions of acid:
(a) 8.00 mL
pH =
(b) 29.80 mL
pH =
(c) 38.00 mL
pH =

Calculate the pH during the titration of 30.00 mL of 0.1000 M
KOH with 0.1000 M HBr solution after the following additions of
acid: (a) 5.00 mL (b) 29.50 mL (c) 36.00 mL

what is the ph of a solution that is .15 M in HNO3 and 2.0 M
HCN?

A)
Calculate the pH of a .01M KOH solution in water at 25 degrees C
B) What is the percentage of .01M acetic acid dissociated at
25 degrees C?

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