Will the pH of hydrogen fluoride be greater or less than 7?

Answer 1

Yes. HCl of the same concentration (0.01 M) has a pH of 2, or is a strong acid. HF is a weak acid, meaning that it would indeed have a pH that is higher than 2 or is closer to being neutral

Answer 2

Any acid has a pH of less than 7.0, so the pH will be lower than 7.0. HF however is not a strong acid as it has a low tendency to dissociate and so the concentration of H+ iones it produces (denoted as [H+] or as [H30+] ) will be low. This is due to its high electronegativity. However when it does dissociates that same electronegativity allows it to grab onto anything in order to complete its octet. HF is highly corrosive and can "eat" through glass stone and skin. It is this aspect of its chemical nature that leads people to falsely label it a strong acid. In other words the question is improperly phrased as HF is not a strong acid.

The p in ph stands for negative log and H in pH stands for H+ concentration. pH is derived from the equation pH= -log[H+]. So naturally you ask how do we find [H+] We need to look up in a table the ka value of HF. The ka value of HF is 6.3 x 10

-4

. ka value of any acid is given by the concentration of the products divided by the concentration of the reactants once the reaction has reached equilibrium (ie when the concentrations of the products and reactants stays the same.) We then generate the following equation using an ice table (I.C.E Stands for "I"nitial concentration. "C"hange in concentration. And then Concentration at "E"quilibrium. Assume at the start HF had a molarity (M/L) of 1.0 M. Then initially we have 0 reactants (H+ and F-) the change we will denote with X since we don't know what it is. HF will lose X concentration and H+ and F- will gain x concentration once it reaches equilibrium. This information yields us the following table.)

HF=== H30+ + F- but pure liquids and solids like water do not show up in our equation for Ka so for simplicities sake it was removed in the previous equation.)

Since a decrease in pH means an increase in acidicy our new pH of 1.60 is more acidic then the pH of 7.0 water (which is always the pH of DI water at 25 degrees C) and has a lower pH. Write that as your answer and see what you get. lol

I know this might seem like a bit of over kill but it completely answers your question. I personally never like to just have an answer but rather I prefer to have an understanding.

Answer 3

im doing this for a class online. im a sophmore in high... what does this even mean?

Answer 4

It will be less than seven as it is an acid

Answer 5

that depends on whether it is acidic or basic - or neutral if it is exactly 7.0

Answer 6

The pH of the solution will be less than seven, because all acids have a pH less than seven.

Answer 7

Acid solutions always have a pH less than 7 (neutral). Bases have a ph greater than 7.

Answer 8

less than 7

Answer 9

less than.