Acids and Bases and water

[Sean1F]

Hi Hi Hi. On one of the lecture problems, a very strong acid or base is added to the water equation and from that, we somehow know or can easily estimate the resulting pH or equilibrium constant. Why is that? I understand that equilibrium constant for H3O and OH always adds up to 10^-14, but how can we predict the results??

[Anthony Tam]

This is because strong acids dissociate completely in water. So the [H3O+] is essentially the same thing as the initial strong acid concentration.

[Sean1F]

This is because strong acids dissociate completely in water. So the [H3O+] is essentially the same thing as the initial strong acid concentration.

Anthony u a real one

[Cassidy Chiong 2J]

A very strong acid or base completely dissociates in water. So through stoichiometry, we can calculate the molarity of H+ ions or OH- ions produced from the given molarity of the acid/base pretty easily.

[Michelle Gong]

HI Sean!
As the others have said, when dealing with strong acids like HCl and strong bases like group 1 and 2 hydroxides, we can be fairly confident that most of it dissociates and we can rely on the stoichiometric ratios found in the balanced equation for the reaction. This being said, if we were dealing with weak acids and bases, we immediately need to implement an ICE box, as we need to know the percent ionization that occurred, as it is more stable when it is together.

[Aditya Desai 1A]

Strong acids dissociate completely.

[Abu Zhang 2D]

Strong acids dissociate completely, so [H3O+] would be the same as the concentration of that strong acid. We only need to use the pKa etc. to calculate [H3O+] when dealing with weak acids.

[RobinFong_2B]

A characteristic of a strong acid is that it completely disassociates in water. So the pH can easily be calculated using stoichemetry.

[Dillon Taing 3H]

To calculate the pH of an acid or base, you only need the H+ or OH- concentration. Because strong acids and bases dissociate completely in water, we are able to use the molarity of these ions to find the pH or equilibrium constant.

[Nishan Reddy 3K]

Because strong acids completely dissociate in water and the kw remains the same, the concentration of the H3O+ is assumed to just be the amount of H+ given off by the strong acid so we base the pH around this value. We do not need to know the OH- concentration since it will be very small due to the Kw ratio.

[205282258]

strong acids completely dissociate in water, so the concentration of H30+ is the same as the concentration of the acid