- How is potassium dichromate prepared from a sample of chromite ore? Give balanced equations for the chemical reactions involved.
- Explain the preparation of K2Cr2O7 from chromite ore and write the chemical equations involved?
- Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate?
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How is potassium dichromate prepared from a sample of chromite ore? Give balanced equations for the chemical reactions involved.
Preparation of potassium dichromate from chromite ore involves the following steps: (i) Conversion of chromite ore to sodium chromate: It is achieved by roasting finely powdered chromite ore with sodium carbonate and quick lime in excess of air. (ii) Conversion of sodium chromate to sodium dichromate: It is achieved by the action of conc. H 2SO 4 on sodium chromate solution. (iii) Conversion of sodium dichromate to potassium dichromate: It is achieved by treating hot conc. solution of sodium dichromate with KCl. The resulting solution on cooling yields orange crystals of potassium dichromate. Categories • • (31.9k) • (8.8k) • (764k) • (261k) • (257k) • (218k) • (248k) • (2.9k) • (5.2k) • (664) • (121k) • (72.1k) • (3.8k) • (19.6k) • (1.4k) • (14.2k) • (12.5k) • (9.3k) • (7.7k) • (3.9k) • (6.7k) • (63.8k) • (26.6k) • (23.7k) • (14.6k) • (25.7k) • (530) • (84) • (765) • (49.1k) • (63.8k) • (1.8k) • (59.3k) • (24.5k)
Explain the preparation of K2Cr2O7 from chromite ore and write the chemical equations involved?
Potassium dichromate is prepared from chromite ore (FeCr 2O 4) in the following steps. Step (1): Preparation of sodium chromate 4FeCr 2O 4 + 16NaOH + 7O 2→ 8NaCrO 4 + 2Fe 2O 3 + 8H 2O Step (2): Conversion of sodium chromate into sodium dichromate 2Na 2CrO 4 + conc.H 2SO 4→ Na 2Cr 2O 7 + Na 2SO 4 + H 2O Step(3): Conversion of sodium dichromate to potassium dichromate Na 2Cr 2O 7 + 2KCl → K 2Cr 2O 7 + 2NaCl Potassium dichromate being less soluble than sodium chloride is obtained in the form of orange coloured crystals and can be removed by filtration. The dichromate (Cr 2O 2- 7) ion exists in equilibrium with chromate (CrO 2- 4) ion at pH 4. However, by changing the pH, they can be interconverted.
Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate?
Potassium dichromate is prepared from iron chromite ore through the following steps: Step 1: Preparation of sodium chromate: \[FeC + 2NaCl\] As potassium chloride is less soluble than sodium chloride, it is obtained in the form of orange-coloured crystals and can be removed through the process of filtration. The dichromate ion (Cr 2O 7 2-)exists in equilibrium with chromate (CrO 4 2-)ion at pH 4. However, with a change in the pH, they can be inter converted.
