Answer:
pH = 2.462.
Explanation:
Hello there!
In this case, according to the reaction between nitrous acid and potassium hydroxide:

It is possible to compute the moles of each reactant given their concentrations and volumes:

Thus, the resulting moles of nitrous acid after the reaction are:

So the resulting concentration considering the final volume (20.00mL+13.27mL) is:
![[HNO_2]=\frac{6.73x10^{-4}mol}{0.01327L+0.02000L} =0.02023M](https://tex.z-dn.net/?f=%5BHNO_2%5D%3D%5Cfrac%7B6.73x10%5E%7B-4%7Dmol%7D%7B0.01327L%2B0.02000L%7D%20%3D0.02023M)
In such a way, we can write the ionization of this weak acid to obtain:

So we can set up its equilibrium expression to obtain x as the concentration of H3O+:
![Ka=\frac{[NO_2^-][H_3O^+]}{[HNO_2]}\\\\7.1x10^{-4}=\frac{x^2}{0.02023M-x}](https://tex.z-dn.net/?f=Ka%3D%5Cfrac%7B%5BNO_2%5E-%5D%5BH_3O%5E%2B%5D%7D%7B%5BHNO_2%5D%7D%5C%5C%5C%5C7.1x10%5E%7B-4%7D%3D%5Cfrac%7Bx%5E2%7D%7B0.02023M-x%7D)
Next, by solving for the two roots of x, we get:

Whereas the correct value is 0.003451 M. Finally, we compute the resulting pH:

Best regards!
To solve this equation you can use a basic molarity formula and substitute the correct values.
The formula for molarity is M = mol/L.
Start by changing your mL to L. To do this, divide 25 by 1000.
This results in:
.025 L
You can now rearrange your molarity formula to isolate what you are solving for, which is moles.
This leaves your formula as:
ML = mol
Now, plug in your converted volume and given molarity into the formula.
This leaves you with:
(0.100)(0.025) = mol
Multiply to find your final value for moles.
This results in:
0.0025 mol of HNO3
I hope this is what you’re looking for! :)
Answer:
a nonspontaneous redox reaction