Assuming equal concentrations , rank these solutions by pH. RbOH(aq), NH3(aq), HF(aq) HBr(aq), Ca(OH)2(aq).

I know the most acidic solution has the lowest pH and the most basic solution has the highest pH. But how am i supposed to know the pH if i don't know the concentration of each solution?

Order is

Ca(OH)2
RbOH
NH3
HBrO
HNO3

It was on my homework too and this came out right

To determine the order of solutions by pH, you can use the concept of relative acid-base strengths. While you might not have the exact concentrations of each solution, you can still make an assessment by comparing the relative strengths of the acids and bases involved.

Let's go through each compound and evaluate their acid-base properties:

1. HF(aq) - Hydrofluoric acid is a weak acid. It partially dissociates in water to release H+ ions. Since it is a relatively weak acid, it will have a higher pH.
2. HBr(aq) - Hydrobromic acid is a strong acid. It fully ionizes in water, releasing a large amount of H+ ions. It will have a lower pH compared to HF(aq).
3. NH3(aq) - Ammonia is a weak base. It accepts H+ ions to form NH4+. Since it is a relatively weak base, it will have a higher pH.
4. Ca(OH)2(aq) - Calcium hydroxide is a strong base. It fully ionizes in water, releasing a large amount of OH- ions, which reacts with H+ ions to form water. It will have a higher pH compared to NH3(aq).
5. RbOH(aq) - Rubidium hydroxide is also a strong base. It fully dissolves in water, releasing a large amount of OH- ions. Like Ca(OH)2(aq), it will have a higher pH.

Based on this analysis, we can rank the solutions from lowest to highest pH:

HBr(aq) < HF(aq) < NH3(aq) < Ca(OH)2(aq) < RbOH(aq)

Please note that even if the exact concentrations are not known, we can still predict the relative order based on the acid-base properties of each compound.

I think the secret is in the wording of the problem. It says assuming EQUAL concns.....

I would divide these into bases and acid.
bases:
RbOH, NH3 and Ca(OH)2.
RbOH is the highest OH, followed by Ca(OH)2 and NH3. I rank RbOH higher than Ca(OH)2 because Ca(OH)2 isn't a soluble as RbOH.

acid:
HBr, HF
HBr is a strong acid; HF is a weak acid. You should be able to rank all of them now.

HI+RbOH=

In acids, more electronegativity is more acid power.

In bases, less electronegativity is more bas power.

Because H is positive and elements with high electronegativity pushs more H+. So with this our acid will be more powerful.

And as same as acids, we calculate bases powers with this way.

Less electronegative elements pushes more OH-. So our bas becomes more powerful.

NO idea