Indicate whether each of the following statements is true or...

Indicate whether each of the following statements is true or false. For each statement that is false, correct the statement to make it true. (a) Acid strength in a series of $\mathrm{H}-\mathrm{A}$ molecules increases with increasing size of A. (b) For acids of the same general structure but differing electronegativities of the central atoms, acid strength decreases with increasing electronegativity of the central atom. (c) The strongest acid known is HF because fluorine is the most electronegative element.

Key Concepts

Acid Strength

Acid strength refers to the ability of a compound to donate a proton (H?) in solution. It is largely determined by how easily the bond between hydrogen and the rest of the molecule breaks and by the stability of the conjugate base formed once the proton has been donated.

Periodic Trends

Periodic trends, such as changes in atomic size and bonding characteristics as one moves down or across a group in the periodic table, significantly affect acid strength. For example, as atomic size increases, the H–A bond typically becomes longer and weaker, thereby facilitating easier proton loss and stronger acidic behavior.

Electronegativity

Electronegativity describes an atom’s ability to attract electrons, which can polarize bonds and affect acidity. However, higher electronegativity does not always correlate with stronger acids because other factors, such as bond strength and the ability of the conjugate base to stabilize charge through polarizability, also play critical roles.

Bond Strength

Bond strength between hydrogen and the atom to which it is attached is a key factor in determining an acid’s strength. A weaker bond will more readily release the proton, leading to a stronger acid. This concept underpins the periodic trend where acids with larger, more polarizable atoms typically exhibit weaker bonds and increased acid strength.

Conjugate Base Stability

The stability of the conjugate base formed after the loss of a proton is crucial for determining acid strength. A more stable conjugate base, due often to factors like charge delocalization, larger atomic radius, and increased polarizability, will favor acid dissociation, making the parent acid stronger.

Transcript

00:01 Chapter 16, problem 92 of chemistry, the central science.

00:05 We're going to be determining if the statement is true or false and then correcting the false statements.

00:11 So for a, it is stating acid strengths in a series of h -to -a molecules increased with the increasing the size of a.

00:23 So what it's asking is that if a increases, so does the strength of the acidity? so i'm going to, this is true, and the reason why this is true is because the larger, the a molecule gets, the longer that bond length between hydrogen and the other molecule has to get.

00:50 And so therefore the easier for that hydrogen bonding to be, the hydrogen to be broken between the h and the other molecule.

01:00 So this is going to be true.

01:03 And it's due to the atomic radius.

01:06 And the larger it gets, the larger the bond distance has to be between the h and the b.

01:14 All right.

01:15 So for b, it says for acids in the same general structure, but differing electromagnetitivities for the central atoms, acids strength decrease with increasing electro -negativity of the central atoms.

01:28 So the first thing to know is that our electronegativity trend goes up and over.

01:37 Also, something to some groups to look at is if we are looking at just the halogen acid.

01:44 So if you have hf, h -c -l, h -b -r, and h -i, we know that h -c -l -h -r and h -i, is stronger than hvr and hbi...

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