Practice questions covering the properties, reactions, and applications of d and f block elements, including transition metals, lanthanides, and actinides.
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
