$$\underline A \,\,\buildrel {4KOH,{O_2}} \over \longrightarrow \,\,\mathop {2\underline B }\limits_{\left( {Green} \right)} \,\, + \,\,2{H_2}O$$

$$3\underline B \,\,\buildrel {4HCl} \over \longrightarrow \,\,\mathop {2\underline C }\limits_{\left( {Purple} \right)} \,\, + \,\,Mn{O_2} + 2{H_2}O$$

$$2\underline C \,\,\buildrel {{H_2}O.KI} \over \longrightarrow \,\,\mathop {2\underline A }\limits_{\left( {Purple} \right)} \,\, + \,\,2KOH\,\, + \,\,\underline D $$

In the above sequence of reactions, $${\underline A }$$ and $${\underline D }$$, respectively, are :

Taj Mahal is being slowly disfigured and discoloured. This is primarily due to :

Among the colloids cheese (C), milk (M), and smoke (S), the correct combination of the dispersed phase and dispersion medium, respectively is :

The standard reaction Gibbs energy for a chemical reaction at an absolute temperature T is given by $$\Delta $$_rG^o = A – BT

Where A and B are non-zero constants. Which of the following is TRUE about this reaction?