Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R

Assertion A : Permanganate titrations are not performed in presence of hydrochloric acid.

Reason R : Chlorine is formed as a consequence of oxidation of hydrochloric acid.

In the light of the above statements, choose the correct answer from the options given below

The plot of $$\mathrm{pH}$$-metric titration of weak base $$\mathrm{NH}_{4} \mathrm{OH}$$ vs strong acid HCl looks like :

Class XII students were asked to prepare one litre of buffer solution of $$\mathrm{pH} \,8.26$$ by their Chemistry teacher: The amount of ammonium chloride to be dissolved by the student in $$0.2\, \mathrm{M}$$ ammonia solution to make one litre of the buffer is :

(Given: $$\mathrm{pK}_{\mathrm{b}}\left(\mathrm{NH}_{3}\right)=4.74$$

Molar mass of $$\mathrm{NH}_{3}=17 \mathrm{~g} \mathrm{~mol}^{-1}$$

Molar mass of $$\mathrm{NH}_{4} \mathrm{Cl}=53.5 \mathrm{~g} \mathrm{~mol}^{-1}$$ )

$${K_{{a_1}}}$$, $${K_{{a_2}}}$$ and $${K_{{a_3}}}$$ are the respective ionization constants for the following reactions (a), (b) and (c).

(a) $${H_2}{C_2}{O_4} \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} {H^ + } + H{C_2}O_4^ - $$

(b) $$H{C_2}O_4^ - \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} {H^ + } + {C_2}O_4^{2 - }$$

(c) $${H_2}{C_2}O_4^{} \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}} 2{H^ + } + {C_2}O_4^{2 - }$$

The relationship between $${K_{{a_1}}}$$, $${K_{{a_2}}}$$ and $${K_{{a_3}}}$$ is given as :