the solution with the lowest pH is
A. 1.0 M HF
B. 1.0 M HCN
C. 1.0 M HCOOH
D. 1.0 M CH3COOH
and how did you find it?
You COULD work each one for pH and see which is the lowest but that isn't necessary. I'll show you how to do one of them, HF since it is first.
.............HF ==> H^+ + F^-
initial......1.0.....0.....0
change.......-x......x......x
equil......1.0-x.....x.......x
Look up Ka. In my text Ka is listed as 7.2E-4
Ka = (H^+)(F^-)/(HF)
7.2E-4 = (x)(x)/(1-x)
Solve for x = 0.0268 M = (H^+) and pH = 1.57.
In a similar manner the pH of the other acids can be calculated, then compared to pick the one with the lowest pH.
BUT you can reason which will have the lowest pH. Low pH means highest acidity and highest acidity means the one with the largest Ka which means the strongest acid. (Note the M is the same and all have just one H atom/molecules.)
So
Ka HF = 7.2E-4
Ka HCN = 2.1E-9
Ka HCOOH = 1.77E-4
Ka CH3COOH = 1.8E-5
Based on these values I would pick HF as the strongest acid leading to the lowest pH. However, you should check in your text for Ka for each acid and pick the one with the largest Ka value.
Ah, pH, the scale that measures how acidic or basic a solution is. Well, let me juggle these choices and find the most acidic one for you!
Hmm, let's start by ruling out some contenders. A clown always knows that strong acids are more acidic than weak ones. So, sorry HCOOH and CH3COOH, but you're outta the running!
Now, we're left with HF and HCN. Time for a clown magic trick! Abracadabra... *poof* the answer is B. 1.0 M HCN! HCN is a weak acid, but compared to HF, it wins the contest of acidity.
Now, isn't that pH-un?
To find the solution with the lowest pH among the given options (A, B, C, and D), we need to compare their acidic properties. The lower the pH, the more acidic the solution.
To determine acidity, we can look at the strength of the acids and their corresponding conjugate bases. Stronger acids have a tendency to donate protons (H+ ions) more readily, resulting in a lower pH.
Now, let's evaluate each option:
A. 1.0 M HF (hydrofluoric acid) - HF is a weak acid. It partially ionizes in water to produce H+ ions and F- ions. It has a higher pH compared to strong acids.
B. 1.0 M HCN (hydrocyanic acid) - HCN is also a weak acid. It partially ionizes in water to produce H+ ions and CN- ions. It has a higher pH compared to strong acids.
C. 1.0 M HCOOH (formic acid) - HCOOH is a weak acid as well. It partially ionizes in water to produce H+ ions and HCOO- ions. It has a higher pH compared to strong acids.
D. 1.0 M CH3COOH (acetic acid) - CH3COOH is a weak acid. It partially ionizes in water to produce H+ ions and CH3COO- ions. It has a higher pH compared to strong acids.
Among the options, the solution with the lowest pH is the one with the strongest acid. Since all options are weak acids, their pH values will be relatively high. So, we cannot determine a clear winner just by comparing the acids given.
To determine the solution with the lowest pH among the given options, we need to consider the acidity of each compound.
The acidity of a compound is commonly determined by the presence of hydrogen ions (H+) in the solution. The more hydrogen ions a solution has, the lower its pH will be.
Now, let's evaluate each option:
A. 1.0 M HF: Hydrofluoric acid (HF) is a weak acid. However, it still ionizes to produce hydrogen ions and fluoride ions. Thus, it contributes to the acidity of the solution.
B. 1.0 M HCN: Hydrocyanic acid (HCN) is also a weak acid. When it dissolves in water, it produces hydrogen ions and cyanide ions. This also contributes to the acidity of the solution.
C. 1.0 M HCOOH: Formic acid (HCOOH) is a weak acid as well. It ionizes in water to produce hydrogen ions and formate ions, contributing to the solution's acidity.
D. 1.0 M CH3COOH: Acetic acid (CH3COOH) is a weak acid too. It ionizes in water to produce hydrogen ions and acetate ions, similar to the other acids.
After considering the ionization of each compound, we can conclude that the solution with the lowest pH is:
B. 1.0 M HCN
This is because HCN is a stronger weak acid compared to the others. It ionizes to a greater extent, producing a higher concentration of hydrogen ions and, consequently, resulting in a lower pH.
To determine this, you can use the knowledge of acid strength and ionization constants, or you can experimentally measure the pH values of each solution using a pH meter.