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 $\rightarrow$
A solution of weak acid $HA$ containing $0.01$ moles of acid per litre of solutions has $pH = 4$. The percentage degree of ionisation of the acid and the ionisation constant of acid are respectively.
$0.1$ $mol$ of $H_2S(g)$ is kept in a $0.4$ litre vessel at $1000\,K$. For the reaction -
$2{H_2}S(g)\,\rightleftharpoons\,2{H_2}(g)\, + \,{S_2}(g)\,;\,{K_c} = {10^{ - 6}}\% $ dissociation of $H_2S$ is.......$\%$
The $pH$ of $0.005 \,M$ codeine $\left( C _{18} H _{21} NO _{3}\right)$ solution is $9.95 .$ Calculate its ionization constant and $p K_{ b }$
Derive the equation of relation between weak base ionization constant ${K_b}$ and its conjugate acid ionization constant ${K_a}$
At $25\,^oC$, the dissociation constant of $CH_3COOH$ and $NH_4OH$ in aqueous solution are almost the same. The $pH$ of a solution $0.01\, N\, CH_3COOH$ is $4.0$ at $25\,^oC$. The $pH$ of $0.01\, N\, NH_4OH$ solution at the same temperature would be