JEE MAIN - Chemistry (2019 - 11th January Evening Slot - No. 16)
$$\underline A \,\,\buildrel {4KOH,{O_2}} \over
\longrightarrow \,\,\mathop {2\underline B }\limits_{\left( {Green} \right)} \,\, + \,\,2{H_2}O$$
$$3\underline B \,\,\buildrel {4HCl} \over \longrightarrow \,\,\mathop {2\underline C }\limits_{\left( {Purple} \right)} \,\, + \,\,Mn{O_2} + 2{H_2}O$$
$$2\underline C \,\,\buildrel {{H_2}O.KI} \over \longrightarrow \,\,\mathop {2\underline A }\limits_{\left( {Purple} \right)} \,\, + \,\,2KOH\,\, + \,\,\underline D $$
In the above sequence of reactions, $${\underline A }$$ and $${\underline D }$$, respectively, are :
$$3\underline B \,\,\buildrel {4HCl} \over \longrightarrow \,\,\mathop {2\underline C }\limits_{\left( {Purple} \right)} \,\, + \,\,Mn{O_2} + 2{H_2}O$$
$$2\underline C \,\,\buildrel {{H_2}O.KI} \over \longrightarrow \,\,\mathop {2\underline A }\limits_{\left( {Purple} \right)} \,\, + \,\,2KOH\,\, + \,\,\underline D $$
In the above sequence of reactions, $${\underline A }$$ and $${\underline D }$$, respectively, are :
Kl and KMnO4
Kl and K2MnO4
KlO3 and MnO2
MnO2 and KlO3
Explanation
$$Mn{O_2}(A) \,\,\buildrel {4KOH,{O_2}} \over
\longrightarrow \,\,\mathop {2K_2MnO_4(B) }\limits_{\left( {Green} \right)} \,\, + \,\,2{H_2}O$$
$$3K_2MnO_4(B) \,\,\buildrel {4HCl} \over \longrightarrow \,\,\mathop {2K_2MnO_4(C) }\limits_{\left( {Purple} \right)} \,\, + \,\,Mn{O_2} + 2{H_2}O$$
$$2K_2MnO_4(C) \,\,\buildrel {{H_2}O.KI} \over \longrightarrow \,\,\mathop {2 Mn{O_2}(A) }\limits_{\left( {Purple} \right)} \,\, + \,\,2KOH\,\, + \,\,KIO_3(D) $$
$$ \therefore $$ A $$ \to $$ MnO2
D $$ \to $$ KIO3
$$3K_2MnO_4(B) \,\,\buildrel {4HCl} \over \longrightarrow \,\,\mathop {2K_2MnO_4(C) }\limits_{\left( {Purple} \right)} \,\, + \,\,Mn{O_2} + 2{H_2}O$$
$$2K_2MnO_4(C) \,\,\buildrel {{H_2}O.KI} \over \longrightarrow \,\,\mathop {2 Mn{O_2}(A) }\limits_{\left( {Purple} \right)} \,\, + \,\,2KOH\,\, + \,\,KIO_3(D) $$
$$ \therefore $$ A $$ \to $$ MnO2
D $$ \to $$ KIO3
Comments (0)
