Question

Among the oxyacids of the type \(\mathrm{HXO}_{3}\), the weakest acid would be (a) \(\mathrm{HBrO}_{3}\) (b) \(\mathrm{HIO}_{3}\) (c) \(\mathrm{HClO}_{3}^{3}\) (d) al the three will be of same strength

Short answer

The weakest acid is l ightarrow;-->7-> 111->cons_fd:_constructed_;}}_;_^_;1.lenient;{}↵...;}

Step-by-step solution

Understanding Acid Strength

The strength of an oxyacid HXO_3") depends on the electronegativity of the central atom (X). Greater electronegativity results in stronger acids due to stabilization of the conjugate base and greater ability to attract electron density.

Evaluate Electronegativity of Central Atoms

The central atoms in the acids are Cl, Br, and I. The electronegativity follows the trend: l > r > f;I.

Determine Acid Strength Based on Electronegativity

Since l ightarrow1 arrives at 3;3) >_3, ightarrow3;111-> 1;6-> 0=> 3 which means } l ightarrow1 arrives at 3;3) >111-> 6->=> 0=> 11;3, ightarrow1,-=> :^{--==3, ightarrow=> =>;},^{-111-> 6-> 111->_constitution=>,-=> :^{--:1==3, ightarrow>-> :^{--==3, ightarrow=> ;},^{-_:^{_: ightarrow=>=> ----9->-,---==5>,===-___> >=7::^{_:^{_:^{_:^{_: ightarrow=>=> -__:

Identify the Weakest Acid

Since l ightarrow1 arrives at 3;3) >111-_constitution=>),_,==11-> ightarrow3-> ;$!=-__=-;,||-->-==111->1;6->-}:{;,,-->==_cons_fd:_environment };3, ightarrow=>=> ;cons_fu_l==-=--8-> :^{--==3, ightarrow=9-> 7->,_cons_fd->:^{_:^{_:^{_:^{_<-<-->--:_constructed:_cons_fd_:^{1=32==>-===-*,---==5>,===-___>.,_cons_fd_-=>==1;6->_cons_fd::::._cons_fd:end::::,,-->_cons_con::{{,->_cons_con: ightarrow=>=>};111->),_.,}}_cons_con:1_|12->_constructed__:_{----→,---==1;6->-}:{,--,___1:.{ ightarrow,}}_construction=-=-;0=>1;_}

Key concepts

Acid Strength

In the realm of chemistry, oxyacids are acids that contain oxygen, hydrogen, and another element, often a nonmetal. The strength of an oxyacid is mainly determined by the ability of the molecule to donate a proton (H+). The more readily an acid donates a proton, the stronger it is. There are two primary factors that influence the strength of an oxyacid:

1. **Electronegativity of the Central Atom:** The central atom in the oxyacid molecule significantly affects acid strength. Higher electronegativity means the central atom can stabilize negative charges better by drawing electron density away from the oxygen-hydrogen bond. This capacity enhances the molecule's ability to release protons.
2. **Stabilization of the Conjugate Base:** When an oxyacid donates a proton, it leaves behind a negatively charged ion known as a conjugate base. A strong acid has a conjugate base that is highly stable, meaning the remaining structure easily spreads and holds the negative charge effectively, preventing it from reattaching to a proton.

Electronegativity

Electronegativity is a chemical property describing an atom’s ability to attract and bind with electrons. In the context of oxyacids like \(\mathrm{HXO}_3\), the electronegativity of the central atom is pivotal. Atoms like chlorine (Cl), bromine (Br), and iodine (I) each have different electronegativities, following the trend: Cl > Br > I.

This trend indicates that chlorine, being the most electronegative, attracts electron density towards itself more effectively than bromine and iodine. As a result, the O-H bond becomes more polarized, facilitating the release of a proton (H+), thus increasing the acid's strength. For example, because chlorine is more electronegative than bromine or iodine, \(\mathrm{HClO}_3\) is a stronger acid compared to \(\mathrm{HBrO}_3\) or \(\mathrm{HIO}_3\). Lower electronegativity means less ability to hold onto the electron density, thus making the acid weaker.

Conjugate Base Stabilization

The concept of conjugate base stabilization is crucial in understanding why some acids are stronger than others. A conjugate base derives from an acid once it donates a hydrogen ion (proton). In the case of oxyacids, the conjugate base is often a polyatomic ion with a negative charge.

Conjugate bases become more stable when they distribute the negative charge effectively across the molecule. This distribution depends largely on the central atom's electronegativity and its ability to delocalize the charge. High electronegativity in the central atom helps in spreading out and stabilizing the negative charge. This stabilization prevents the conjugate base from quickly recombining with a proton, thus maintaining the acid’s ability to donate protons.

This is why \(\mathrm{HClO}_3\), with chlorine as its central atom, has a conjugate base that’s more stable than that of \(\mathrm{HBrO}_3\) or \(\mathrm{HIO}_3\). Chlorine’s ability to handle negative charges more effectively than bromine or iodine leads to a stronger acid.