Discuss the factors affecting acid strength by examples.
At experimentally, the strength of acid base decided by the value of $\mathrm{pH}$.
Theoretically the extent of dissociation of an acid depends on the strength and polarity of the $\mathrm{H}$ - $A$ bond. i.e. $\left[\mathrm{H}^{+}\right]$and strength will be decide.
$(i)$ When strength of $\mathrm{H}-\mathrm{A}$ bond decreases, that is, the energy required to break bond decreases, $HA$ becomes a stronger acid.
$(ii)$ When the $\mathrm{H}-\mathrm{A}$ bond becomes more polar, i.e. the electronegativity difference between the atoms $\mathrm{H}$ and A increases and there is marked charge separation, clavate of the bond becomes easier there by increasing the acidic. Thus, polarity of bond $\alpha$ difference of electronegativity $\alpha$ Acidity.
$(iii)$ The strength of $\mathrm{H}-\mathrm{A}$ in only one period : In the row of the periodic table, $\mathrm{H}-\mathrm{A}$ bond polarity becomes the deciding factor for determining the acid strength. As the electronegativity of a increases, the strength of acid also increases. For example, $\rightarrow$ Electronegativity A increases $\rightarrow \mathrm{CH}_{4}<\mathrm{NH}_{3}<\mathrm{H}_{2} \mathrm{O}<\mathrm{HF} \rightarrow$ Acid strength increases $\rightarrow$ The acidic strength in group : In the group of the periodic table, $H$ - $A$ bond strength is a more important factor in determining acidity than its polar nature. As the size of $\mathrm{A}$ increases down the group. $\mathrm{H}-\mathrm{A}$ bond strength decreases and so the acid strength increases. For example,
$\rightarrow$ Size increases of $\mathrm{A} \rightarrow \mathrm{HF} \ll \mathrm{HCl} \ll \mathrm{HBr} \ll \mathrm{HI} \rightarrow$ Acid strength increases $\rightarrow$
If degree of ionisation is $0.01$ of decimolar solution of weak acid $HA$ then $pKa$ of acid is
A monoprotic acid in a $0.1\,\,M$ solution ionizes to $0.001\%$. Its ionisation constant is
$HClO$ is a weak acid. The concentration of ${H^ + }$ ions in $0.1\,M$ solution of $HClO\,({K_a} = 5 \times {10^{ - 8}})$ will be equal to
A weak acid is $ 0.1\% $ ionised in $0.1\, M $ solution. Its $pH$ is
Heat of neutralisation of weak acid and strong base is less than the heat of neutralisation of strong acid and strong base due to