Question

Calculate the p"' of 0.90M HPO,?Ka HPOA≥ = 4.5 x 10-13(a) 7(b) 14(c) 12.3(d) 8.20(e) 6.20

Answer 1

(e) 6.20

Step-by-step explanation

The pH of the solution can be calculated using the formula below:

`pH=(1)/(2)pKa-(1)/(2)log\text{ }c`

Note that:

`pKa=-log\text{ }Ka`

Put Ka = 4.5 x 10⁻¹³ into the pKa formula:

`pKa=-log(4.5*10^(-13))=12.35`

Put pKa = 12.35 and c = 0.90 into the pH formula above:

`\begin{gathered} pH=(1)/(2)(12.35)-(1)/(2)(log\text{ }0.90) \\ \\ pH=6.175-(1)/(2)(-0.0458) \\ \\ pH=6.175+0.0229 \\ \\ pH=6.1979 \\ \\ pH\approx6.20 \end{gathered}`

The pH = 6.20

The correct option is (e) 6.20