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KMnO_4 acts as an oxidising agent in acidic medium. 'X' is the difference between the oxidation states of Mn in reactant and product. 'Y' is the number of 'd' electrons present in the brown red precipitate formed at the end of the acetate ion test with neutral ferric chloride. The value of X + Y is ______.

Numerical Answer Type:
Enter a numerical value Answer: 10 to 10 +4 marks

Solution & Explanation

### Core Logic Let's resolve both components step by step: 1. **Finding X:** In an acidic medium, the permanganate ion (KMnO_4, where Mn is in the +7 state) is reduced to the divalent manganese cation (Mn^2+, state +2): X = 7 - 2 = 5 2. **Finding Y:** During qualitative salt analysis, the acetate ion reacts with neutral ferric chloride to produce a characteristic blood-red coordination solution. Boiling this solution throws down a **brown-red precipitate** of basic ferric acetate, [Fe(OH)_2(CH_3COO)]. In this complex, Iron retains its +3 oxidation state: Fe^3+ implies [Ar] 3d^5 4s^0 implies textNumber of d-electrons (Y) = 5 Summing the values yields: X + Y = 5 + 5 = 10 ### Pattern Recognition This problem elegantly links standard redox transitions with qualitative inorganic salt tests. Remember that throughout the basic ferric acetate precipitation test, Iron remains steadily in its ferric +3 (d^5) core configuration. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: The d- and f-Block Elements Inorganic Qualitative Analysis

Reference Study Guides

More The d- and f-Block Elements Previous-Year Questions — Page 3

Q47 2025 Preparation and Properties of Potassium Dichromate
The molar mass of the water insoluble product formed from the fusion of chromite ore mathrm(FeCr_2O_4) with mathrmNa_2mathrmCO_3 in presence of mathrmO_2 is ________ mathrmg \, mol^-1.
Numerical Answer. Answer: 160 to 160

Solution

### Related Formula textBalanced fusion reaction process description ### Core Logic Write the balanced chemical equation for the industrial preparation stage of chromate salts : 4mathrmFeCr_2O_4 + 8mathrmNa_2CO_3 + 7mathrmO_2 ightarrow 8mathrmNa_2CrO_4 + 2mathrmFe_2O_3 + 8mathrmCO_2 Evaluating the solubilities of the products: * mathrmNa_2CrO_4 is highly soluble in water. * mathrmFe_2O_3 (Iron(III) oxide) is water-insoluble . Molar Mass of mathrmFe_2O_3 : M = (2 cdot 55.85) + (3 cdot 16.0) simeq (2 cdot 56) + (3 cdot 16) = 112 + 48 = 160 \, mathrmg/mol ### Pattern Recognition Transition metal oxides in high oxidation states with minimal ionic breakdown parameters reliably act as insoluble precipitates in water. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: The d-and f-Block Elements

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