In pure water, some of the molecules ionize according to the equation H2O→H+ + OH−. The extent of the ionization increases with temperature. A student heats pure water and records the measured pH at 50°C as 6.6. Based on this information, what mathematical relationships gives the pOH pOH of pure water at 50°C?

Respuesta :

Answer : The mathematical relationships gives the pOH of pure water at [tex]50^oC[/tex] is, [tex]pOH=14-pH[/tex]

Explanation :

As we are given that the pH at [tex]50^oC[/tex] is, 6.6.

Now we have to determine the mathematical relationships gives the pOH of pure water at [tex]50^oC[/tex].

As we know that:

The ionization of water is:

[tex]H_2O\overset{K_w}\rightarrow H^++OH^-[/tex]

The expression for dissociation constant for water is:

[tex]K_w=[H^+][OH^-][/tex]

taking logarithm on both side, we get:

[tex]\log K_w=\log [H^+]+\log [OH^-][/tex]

Taking negative sign on both side, we get:

[tex]-\log K_w=-\log [H^+]+(-\log [OH^-])[/tex]

[tex]pK_w=pH+pOH[/tex]

As we know that the value of [tex]pK_w[/tex] is 14 at 25-50°C.

So,

[tex]14=pH+pOH[/tex]

or,

[tex]pOH=14-pH[/tex]

[tex]14=6.6+pOH[/tex]

[tex]pOH=7.4[/tex]

Therefore, the mathematical relationships gives the pOH of pure water at [tex]50^oC[/tex] is, [tex]pOH=14-pH[/tex]

Ionization is the process in which an atom or a molecule gains either a positive or negative charge.

The mathematical expression for the given pure water ionization at 50°C  is:

pOH = 14 - pH

Given that:

pH at 50°C  = 6.6

The ionization reaction for the pure water is:

H₂O [tex]\rightarrow[/tex] H⁺  + O

The dissociation constant for the water can be given as:

K[tex]_\text w[/tex] = [ H⁺]  [O⁻]

Taking log:

log K[tex]_\text w[/tex] = log [ H⁺] + log  [O⁻]

Intorducing the negative sign:

- log K[tex]_\text w[/tex] =  -log [ H⁺] + (-log  [O⁻])

pK[tex]_\text w[/tex] = pH + pOH

Now, the value of pK[tex]_\text w[/tex] is 14 at 25-50°C, such that:

14 = pH + pOH

pOH = 14 - pH

14 = 6.6 + pOH

pOH = 7.4

Therefore, the pOH of water at 50°C is 7.4.

To know more about dissociation constant, refer to the following link:

https://brainly.com/question/4218061