Please answer the attached question. Please......... ...

@Parth Verma

Gravimetric analysis belong to the most precise, because contemporary analytical balances make possible determination of the mass of a sample with great accuracy. In these analysis one should obtain high purity compound of the analyzed element or a compound directly obtained from the analyzed substance).

 

This reaction has to be exactly stoichiometric. It is also important that the weighed compound was nonhydroscopic and stable in air, it also better if it has relatively high molecular mass, because in this case the weighing is more precise.

 

Examples of gravimetric analyses of high precision and still often used in practice are, among others: Analysis of iron precipitated as Fe(OH)3 and heated in electric oven at ca. 800°C to oxide Fe2O3;

Analysis of barium precipitated as BaSO4 (or analysis of sulfates precipitated by Ba2+ salts), the precipitate is heated to ca. 500°C;

Analysis of nickel precipitated in form of its complex with dimethylglyoxime (CH₃C(NOH)C(NOH)CH3, known also as “Chugaev salt”, the precipitate has to be dried at 110°C only. 

Let us analyze an alloy containing copper to determine its percent content in it. Copper will be precipitated as CuSCN (solubility product Kso=12.7). This means that Cu2+ ions will be reduced to Cu+ before they are precipitated using SCN.

So the answer is (1) Cu₂ (SCN)₂ 

Hope it Helps!!

 

Regards

Piyush Kumar Behera