Answer :

(i) the chromite ore (FeCr2O4) is fused with sodium hydroxide (NaOH)

4FeCr2O4 +16 NaOH+ 7O2 8Na2CrO4 +2Fe2O3 +8H2O


The yellow solution of sodium chromate is then filtered and acidified with sulphuric acid giving its dichromate.


2Na2CrO4 +H2SO4 Na2Cr2O7 + Na2SO4 +H2O


On cooling, sodium sulphate crystallizes out as Na2SO4.10H2O and is removed.


Na2Cr2O7 +2KCl K2Cr2O7 + 2NaCl


(ii) the pyrolusite ore(MnO2) is oxidised in the presence of potassium hydroxide by heating.


2MnO2 + 4KOH +O2 2K2MnO4 + 2H2O


The green potassium manganate (K2MnO4) is then treated with a current of chlorine or ozone to oxidise potassium manganate to potassium permanganate.


2K2MnO4 +Cl2 2KCl +2KMnO4


K2MnO4 +O3 +H2O 2KMnO4 +2KOH +O2


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses
RELATED QUESTIONS :

Match the catalysChemistry - Exemplar

Indicate the stepNCERT - Chemistry Part-I

What are alloys? NCERT - Chemistry Part-I

Match the compounChemistry - Exemplar

Describe the prepNCERT - Chemistry Part-I

Describe the prepNCERT - Chemistry Part-I

For M2+</supNCERT - Chemistry Part-I

What are interstiNCERT - Chemistry Part-I

(a) Transition meChemistry - Exemplar