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MHT CET · Chemistry · General Principles and Processes of Isolation of Metals

Which of the following is a product of first step and is used as reactant in next step for manufacture of \(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}\) from concentrated chromite ore ?

  1. A Sodium dichromate
  2. B Potassium chromate
  3. C Sodium sulphate
  4. D Sodium chromate
Verified Solution

Answer & Solution

Correct Answer

(D) Sodium chromate

Step-by-step Solution

Detailed explanation

(1) Conversion of chromite ore into sodium chromate
\(\underset{\text { Chromite ore }}{4 FeCr _2 O _4}+8 Na _2 CO _3+7 O _2 \longrightarrow 2 Fe _2 O _3~+\)\(8 CO _2+\underset{\text {Sodium chromate}}{8 Na _2 CrO _4}\)
(2) Conversion of sodium chromate into sodium dichromate
\(\underset{\text { Sodium chromate }}{2 Na _2 CrO _4} + H _2 SO _4 \longrightarrow \underset{\text { Sodium dichromate }}{ Na _2 Cr _2 O _7}\) \(+~ Na _2 SO _4+ H _2 O\)
(3) Conversion of sodium dicbromate to potassium dichromate
\(\underset{\text { Sod. dichromate }}{\mathrm{Na}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}}+2 \mathrm{KCl} \longrightarrow \underset{\text { Pot. dicbromate }}{\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}}+2 \mathrm{NaCl}\)