Chemistry - Salt Analysis Question with Solution | TestHub
A metallic element reacts moderately with dilute , producing a pale-green aqueous solution and a colourless neutral gas. On crystallization, solution yields a pale-green solid which, on strong heating, decomposes into another solid residue and two acidic non-metallic gases.
When X is treated with steam it gives another solid together with evolution of the same colourless gas. Reaction of with dry Cl2 gas produces a brown, covalent solid X5 that sublimes on heating ; the aqueous solution of X5 reacts with copper metal and is therefore used in etching printed - circuit boards.
Addition of NaOH to solution X2 yields a dirty-green precipitate X6, insoluble in excess alkali. On standing in air X6 slowly converts to a foxy-red compound X7. The compound X7 can also be obtained directly by adding NaOH (aq) to an aqueous solution X5.
Identify X1 through X7. and Calculate sum of oxidation states of Metal in X2, X3 , X5, X6 , X7
Answer:
Solution:
(iron, metal)
• X₂ = FeSO₄ (aqueous ferrous sulfate) – pale green solution.
• X₃ = Fe₂O₃ (iron(III) oxide / ferric oxide) – solid residue on strong heating.
• X₄ = Fe₃O₄ (magnetite) – product when Fe reacts with steam.
• X₅ = FeCl₃ (ferric chloride, anhydrous) – brown covalent solid that sublimes; ferric chloride solution etches copper.
• X₆ = Fe(OH)₂ (ferrous hydroxide) – dirty green precipitate, insoluble in excess NaOH.
• X₇ = Fe(OH)₃ (ferric hydroxide / hydrated ferric oxide) – foxy-red product formed on air oxidation or by base addition to FeCl₃.
