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Question : 7
Total: 26
When chromite ore FeCr 2 O 4 NaOH
(A) is obtained which on acidification with dilute sulphuric acid gives a compound (B). Compound
(B) on reaction withKCl
(i) Write the formulae of the compounds (A), (B) and (C).
(ii) Write one use of compound (C).
OR
Complete the following chemical equations:
(i)MnO 4 − + 3 S 2 O 3 2 − + H 2 O →
(ii)Cr 2 O 7 2 − + 3 Sn 2 + + 14 H + →
(A) is obtained which on acidification with dilute sulphuric acid gives a compound (B). Compound
(B) on reaction with
(i) Write the formulae of the compounds (A), (B) and (C).
(ii) Write one use of compound (C).
OR
Complete the following chemical equations:
(i)
(ii)
Solution:
(i) 4 FeCr 2 O 4 + 16 NaOH + 7 O 2 → 8 Na 2 CrO 4 [ A ] + 2 Fe 2 O 3 + 8 H 2 O
Na 2 Cr 2 O 7 [ B ] + 2 KCl → K 2 Cr 2 O 7 [ C ] + 2 NaCl
A : Na 2 CrO 4 B : Na 2 Cr 2 O 7 C : K 2 Cr 2 O 7
(ii) Use ofK 2 Cr 2 O 7 ( C )
OR
(i)8 MnO 4 − + 3 S 2 O 3 2 − + H 2 O → 8 MnO 2 + 6 SO 4 2 − + 2 OH −
(ii)Cr 2 O 7 2 − + 3 Sn 2 + + 14 H + → 2 Cr 3 + + 7 H 2 O + 3 Sn 4 +
(ii) Use of
OR
(i)
(ii)
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