This category covers the preparation methods and key properties of potassium dichromate and permanganate. It is tailored for students preparing for chemistry exams.
In acidic medium, dichromate ion is reduced to Cr 3+ by gaining electrons.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
Interstitial compounds are formed by small atoms (H, C, N) occupying voids in metal lattices. KMnO 4 is an ionic compound.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
K 2 Cr 2 O 7 is an oxidizing agent, not used as a reducing agent.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
Permanganate ion (MnO 4 - ) has tetrahedral geometry with sp 3 hybridization.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
KMnO 4 (Mn in +7 state) readily accepts electrons, making it a strong oxidant.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
KMnO 4 is used as an oxidant, disinfectant, and in organic synthesis, but not as a reducing agent.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
Pyrolusite ore (MnO 2 ) is fused with KOH and oxidized to form KMnO 4 .
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
Dichromate ion consists of two tetrahedral CrO 4 units sharing one oxygen atom (Cr–O–Cr bond angle: 126°).
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
Interstitial compounds are formed when small atoms (H, C, N) occupy voids in metal lattices (e.g., TiC).
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
KMnO 4 is an oxidizing agent, not used as a reducing agent.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
Chromite ore is oxidized with Na 2 CO 3 in the presence of air to form sodium chromate: 4FeCr 2 O 4 + 8Na 2 CO 3 + 7O 2 → 8Na 2 CrO 4 + 2Fe 2 O 3 + 8CO 2 . This is the key step in the preparation of K 2 Cr 2 O 7 .
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
Dichromate (Cr 2 O 7 2− ) converts to chromate (CrO 4 2− ) in alkaline medium: Cr 2 O 7 2− + 2OH − → 2CrO 4 2− + H 2 O. The solution turns yellow due to chromate formation.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Preparation and Properties of Potassium Dichromate and Permanganate
