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1.) Find the pH of 0.080 M in HNO 3 and 0.180 M in HC 7 H 5 O 2 ? 2.) Find the p

ID: 1046671 • Letter: 1

Question

1.) Find the pH of 0.080 M in HNO3 and 0.180 M in HC7H5O2?

2.) Find the pH of 0.025 M in HBr and 0.020 M in HClO4

3.) Find the pH of 0.095 M in HF and 0.230 M in HC6H5O

4.) Find the pH of 0.110 M in formic acid and 0.055 M in hypochlorous acid

Find the pH of each mixture of acids. Acid lonization Constants (Ka) for Some Monoprotic Weak Acids at 25 °C Acid Benzoic acid HC,H502 | 6.5 × 10-5 Hydrofluoric acid HF Phenol Formic acid FormulaKa 6.8 × 10-4 HC6H5O1.3 x 10-10 HCHO21.8 x 104 |2.9 × 10-8 Hypochlorous acid|HClO

Explanation / Answer

Ans 1

HC7H5O2 = benzoic acid

It is a weak acid

Acid dissociation constant

Ka = 6.5x10^-5

HNO3 is a stong acid

[HNO3] = 0.080 M

[H+] = 0.080

Lets prove it

Let HA = benzoic acid

X= H+ from benzoic acid
A-1 = X
6.5x10^-5 = (X+ 0.080)X)/(0.180 - X)
6.5x10^-5 = X^2 + 0.080 X / (0.180 - X)
X^2 + (0.080 + 0.000065) X - 1.17x10^-5 = 0
X^2 + 0.080065X - 1.17x10^-5 = 0
X = 0.00014
It is very small compared to 0.080
pH = -log(0.080) = 1.10