Solution equals 0.015 M HCl

Find OH
Find pH

Isn't pH=1.8?
I don't know how to find OH :(
Is there a formula or do subtract 14-1.8?
I'm confused and I got this assignment today yet we haven't gone over anything yet.

I would not round from 1.82 for pH of 0.015 M HCl. In logarithms the 1 of 1.82 just tells you the location of the decimal point in the 0.015 number so that counts as only two significant figures in 1.82

you can get OH either of two ways.
pH + pOH = 14 and after you know pH you solve for pOH, then convert to OH by pOH = -log(OH^-).
OR you can do
(H^+)(OH^-) = Kw = 1E-14.
You already have H^+ in the problem and you can convert directly to OH this way without going through pH and pOH step.

1. OH= 6.67 *10^-13

Here's what I did
1*10^-14/0.015 M= 6.67*10^-13
2. pH=1.82

Did do it right? Wrong?
Thank you so much for all your help I really appreciate it :)

All of that looks ok to me.

To find the concentration of OH- (hydroxide ion) in a solution, you need to understand the concept of acidity and basicity. Acids have a higher concentration of H+ (hydrogen ions) and lower concentration of OH- ions, while bases have a higher concentration of OH- ions and lower concentration of H+ ions. The pH scale is a measure of the acidity or basicity of a solution, so calculating pH and finding OH- concentration are interrelated.

Let's start by finding the OH- concentration.

1. First, recognize that the given solution is HCl (hydrochloric acid), which is a strong acid. This means that it completely dissociates in water, creating H+ and Cl- ions.
HCl โ†’ H+ + Cl-

2. Since the concentration of HCl is given as 0.015 M, the concentration of H+ ions in the solution is also 0.015 M.

3. Now, consider that water can self-ionize, meaning it can dissociate tiny amounts into H+ and OH- ions.
H2O โ†’ H+ + OH-

4. Due to the self-ionization of water, every time a strong acid (like HCl) donates an H+ ion to the solution, an equal amount of OH- (hydroxide) ions will be formed. This concept is known as the principle of neutralization.

5. In this case, the concentration of HCl is 0.015 M, so the resulting OH- concentration will also be 0.015 M.

So, the concentration of OH- ions in the given solution is 0.015 M.

Next, let's calculate the pH of the solution.

1. The pH scale measures the concentration of H+ ions in a solution. It ranges from 0 to 14, with 7 being neutral (equal concentrations of H+ and OH- ions).

2. To find the pH when the concentration of H+ ions is known, you can use the negative logarithm (base 10) of the H+ concentration. The formula is:
pH = -log[H+]

3. In this case, the concentration of H+ ions is 0.015 M (given as the concentration of HCl).

4. Plug in the value in the formula:
pH = -log(0.015)

5. Use a scientific calculator to evaluate the logarithm:
pH โ‰ˆ 1.82

So, the pH of the solution is approximately 1.82.

To summarize:
- The concentration of OH- ions in the solution is 0.015 M.
- The pH of the solution is approximately 1.82.

Remember, the pH scale is a logarithmic scale, so the difference between two pH values represents a tenfold difference in H+ concentration. Additionally, the pH of an acidic solution is less than 7, while a basic solution has a pH greater than 7.