Chapter 6: Q37P (page 143)

Calculate the pHof pure water at (a) $25 ° C$ and (b) $100 ° C$ .

Short Answer

Expert verified

The pH value at $25 ° C$ is 6.998

The pH value at $100 ° C$ is 6.132

Step by step solution

Formula used

The pH of the solution can be calculated as:

$pH = - \log [H^{+}]$

The formula of the ionic product of water is:

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

Where,

$K_{w} = 1.0 \times 10^{- 14}$

Calculate the pH value at 25°C

(a)

Firstly calculate the pH value at $25 ° C$

$K_{w} = [H^{+}] [{OH}^{-}] = 1.0 \times 10^{- 14}$

Let the concentration of $[H^{+}] = [{OH}^{‐}] = x$

$x^{2} = 1.0 \times 10^{- 14} x = [H^{+}] = 1.005 \times 10^{7} pH = - \log (1.005 \times 10^{- 7}) = 6.998 \approx 7$

(b)

Calculate the pH value at $100 ° C$

At $K_{w} = 5.43 \times 10^{- 14}$

$K_{w} = [H^{+}] [{OH}^{-}] = 5.43 \times 10^{- 13}$

Let the concentration of $[H^{+}] = [{OH}^{‐}] = x$

x^{2} = 5.43 \times 10^{- 13} x = [H^{+}] = 7.368 \times 10^{7} pH = - \log (7.368 \times 10^{- 7}) pH = 6.132

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Calculate the pHof pure water at (a) $25 ° C$ and (b) $100 ° C$ .

Short Answer

Step by step solution

Formula used

Calculate the pH value at 25°C

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Calculate the pHof pure water at (a)25°C and (b)100°C.

Short Answer

Step by step solution

Formula used

Calculate the pH value at 25°C

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Chemistry Textbooks

Chemistry Branches

Chemical Analysis

Ionic and Molecular Compounds

Organic Chemistry

Physical Chemistry

Nuclear Chemistry

Study anywhere. Anytime. Across all devices.

Calculate the pHof pure water at (a) $25 ° C$ and (b) $100 ° C$ .