A 0.040M solution of a monoprotic acid is 14% ionized. Calculate the Ka for the weak acid.

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so:
HX <---> H+ + X-

Ka= [H+][X-]/ [HX]

Since its a monoprotic acis i know the concentration of H and X will be equal

And the HX will be 86% (100%-14%)

BUt i m not sure how to solve for it

So (H^+) = 0.04 x 0.14 = ??

(X^-) is the same.
(HX) = either,
0.04-(0.04*0.14) OR
0.04*0.86 (HX) will be the same no matter which way you go.

To solve for the Ka of the weak acid, we need to use the given information that the solution is 14% ionized and has a concentration of 0.040 M.

Step 1: Calculate the concentration of the ionized forms (H+ and X-).

Since the concentration of H+ is equal to the concentration of X-, we can assume that each ionized form has a concentration of x M.

Step 2: Calculate the concentration of the non-ionized form (HX).

Since the solution is 14% ionized, the concentration of the non-ionized form, HX, will be 86% (100% - 14%) of the total concentration:

[HX] = 0.86 * 0.040 M = 0.0344 M

Step 3: Substitute the concentrations into the expression for Ka.

Ka = [H+][X-] / [HX]

Since [H+] = [X-] = x and [HX] = 0.0344 M, the expression becomes:

Ka = (x)(x) / 0.0344

Simplifying this equation gives:

Ka = x^2 / 0.0344

Step 4: Substitute the given percentage ionization to solve for x.

Since the solution is 14% ionized, the ionized concentration is 0.14 times the total concentration:

x = 0.14 * 0.040 M = 0.0056 M

Step 5: Substitute the value of x into the expression for Ka.

Ka = (0.0056)^2 / 0.0344

Calculating this expression will give you the value of Ka for the weak acid.

To calculate the Ka for a weak acid, you need to know the concentration of the weak acid (HX) and the concentration of its dissociated ions (H+ and X-). You also need to know the percent ionization.

In this case, you're given that the concentration of the weak acid is 0.040M and the percent ionization is 14%. To find the concentration of the dissociated ions, you need to determine what percent of the weak acid has dissociated.

Since the percent ionization is given as 14%, it means that only 14% of the weak acid has dissociated, while the remaining 86% is still in the form of the weak acid (HX).

To find the concentration of the dissociated ions, you can multiply the concentration of the weak acid (0.040M) by the percent ionization (14%) and divide by 100:

[H+] = [X-] = (0.040M) * (14/100) = 0.0056M

So, the concentration of H+ and X- ions is 0.0056M.

Now, you can substitute these values into the Ka equation:

Ka = [H+][X-] / [HX]

Substituting the values:

Ka = (0.0056M) * (0.0056M) / (0.040M)

Simplifying:

Ka = 0.00003136M^2 / 0.040M

Dividing:

Ka = 0.000784M

Therefore, the Ka for the weak acid is 0.000784.