Question

Need Help ASAP

Calculate the pH of:

a) 0.1 M HF Ka = 7.2 x 10-4

b) 1 x 10-3 M HNO3

c) 1 x 10-8 M HCl

Answer 1

a. pH=2.07

b. pH=3

c. pH=8

Further explanation

pH=-log [H⁺]

a) 0.1 M HF Ka = 7.2 x 10⁻⁴

HF= weak acid

`\tt [H^+]=√(Ka.M)\\\\(H^+]=\sqrt{7.2.10^(-4)* 0.1}\\\\(H^+]=8.5* 10^(-3)\\\\pH=3-log~8.5=2.07`

b) 1 x 10⁻³ M HNO₃

HNO₃ = strong acid

`\tt pH=-log[1* 10^(-3)]=3`

c) 1 x 10⁻⁸ M HCl

`\tt pH=-log[1* 10^(-8)]=8`