X(s) (Black) -dil HCl-> Y↑ -Na2[Fe(CN)5(NO)] / NaOH-> Purple solution Gas Y. Gas Y has been allowed — Qualitative and Quantitative Analysis Chemistry Question
Question
X(s) (Black) -dil HCl-> Y↑ -Na2[Fe(CN)5(NO)] / NaOH-> Purple solution Gas Y. Gas Y has been allowed to react with following species in neutral/acidic medium : (a) FeCl3 (b) CuSO4 (c) BaCl2 (d) SO2 (e) Cr2O7^2- (f) CH3COONa (g) Hg2+. Then calculate value of (P + Q - R). P : Number of species which undergoes redox reaction with gas Y. Q : Number of species with which gas Y undergoes precipitation. R : Number of species with which gas Y produce no observable change.
💡 Solution & Explanation
Step 1: Soda extract (sodium carbonate extract) is prepared to bring anions of insoluble salts into a soluble form as sodium salts. Step 2: It is prepared by boiling the mixture with solid sodium carbonate (Na2CO3) in distilled water (typically in a 1:3 ratio) for 10-15 minutes, followed by filtration. Step 3: The boiling with Na2CO3 in distilled water promotes anion exchange to form soluble sodium salts and insoluble metal carbonates, corresponding to option (d).