If the pH of an HCl solution is 3, the H++ ion concentration in its conjugate base is 10−n−n. Find n.

The pH of a solution is defined as the negative logarithm (base 10) of the hydrogen ion concentration. This can be written as:

pH = -log[H+]

If the pH of an HCl solution is 3, we can set up the equation as follows:

3 = -log[H+]

To solve for [H+], we need to get rid of the negative sign and the logarithm. We can do this by taking the inverse log (or 10 to the power of) both sides:

10^3 = [H+]

This gives us [H+] = 0.001 M or 1x10^-3 M.

The conjugate base of HCl is Cl-, which does not contribute to the [H+] in solution. Therefore, the [H+] in the conjugate base solution is the same as in the original HCl solution.

So, the H+ ion concentration in its conjugate base is 10^-n.

Comparing this with the [H+] we calculated earlier (1x10^-3 M), we can see that n = 3.