A Violet Compound of Manganese (A) Decomposes

Que: A violet compound of manganese (A) decomposes on heating to liberate oxygen and compounds (B) and (C) of manganese is formed. Compound (C) reacts with KOH in the presence of KNO₃ to give compound (B). On heating compound (C) with conc. H₂SO₄ and NaCl, Cl₂ gas is liberated and compound (D) of manganese is formed. Identify A, B, C, D along with reactions involved.
Ans: A – KMnO₄                                 B – K₂MnO₄                C – MnO₂                    D – MnCl₂

KMnO₄ → K₂MnO₄ + MnO₂ + O₂ 
(A)              (B)             (C)

MnO₂ + KOH + KNO₃ → 2 K₂MnO₄ + 2 H₂O
(C)                                       (B)

MnO₂ + 4 NaCl + 4 H₂SO₄ (conc.) → MnCl₂ + 2 NaHSO₄ + 2 H₂O + Cl₂
(C)                                                          (D)