pH

[205793570]

How do we know which element has the highest pH by just seeing their formula?
how are we able to put them from lowest to highest such as in question 10 from the achieve homework from week 10?

[105707059]

For question 10 you would identify whether the molecules are acids or bases. We know that the strongest base will have the highest pH. Acids have a lower pH, but strong acids will have the lowest pH. You also need to know how to figure out the relative strength of acids and bases. For acids, the more oxygens, the longer the bond, and the center element with the highest electronegativity will be stronger.

[Fiona Choi 1K]

for "regular" strong acids (such as HCl, HBr, and HI), bigger atoms are stronger. This is due to the fact that a larger atomic radius would result in a longer bond and therefore, a weaker bond. So HI>HBr>HCl. For oxyacids, you can determine relative strength of acids through induction and resonance. A molecule with resonance increases stability as the electron density is shared and spread between the bonds. Induction basically refers to the idea that elements with higher EN will be able to pull electrons away from the H and thus, allowing the H to be donated more easily. For example, HOF will be more acidic than HOCl. Also, more oxygens=higher acidity because the e- density is again, able to be more spread out, pulled away from the H,

[Vivian Kim 3F]

Hi! One way is to first identify whether its a strong base or acid. I tend to just memorize this. For the achieve question, although Ca(OH)2 and RbOH are both strong bases with high pH, Ca(OH)2 produces 2 OH-, while RbOH only produces 1. Therefore Ca(OH)2 is more basic.

[Brianna Mercado 3D]

Hi! In order to calculate the pHs you first ned to identify whether its a strong base or acid

[205282258]

to determine pH first determine whether it is a strong acid/base or not. This will give a general scale of pH. In order to differentiate between two strong acids you can look at their conjugate base. The stronger the conjugate base, the weaker the acid will be(less acidic -> higher pH).