Home
Class 12
CHEMISTRY
Explain the following: (a) Although Au...

Explain the following:
(a) Although Au is soluble in aqua-regia, Ag is not
(b) Zinc and hot copper is used for recovery of Ag from the complex `[Ag(CN)_(2)]^(-)`
(c ) Aluminium metal is frequently used as a reducing agent for extraction of metal such as chromium manganese etc.
(d) Partial roasting of sulphide ore is donue in the metallurgy of copper.

Text Solution

Verified by Experts

(a) Au dissolved in aquaregia forming soluble `HAuCl_(4)` but Ag forms insoluble AgCl
`Au + 4HCl + 3HNO_(3) to underset("soluble")(HAuCl_(4)) + 3NO_(2) + 3H_(2)O`
`Ag + HCl + HNO_(3) to underset("insoluble")(AgCl) + NO_(2) + H_(2)O`
(b) Zinc is powerful reducing agent in comparison to copper and zinc is cheaper also than copper.
(c ) Aluminium metal is frequently used as a reducing agent for the extraction of metals. Such as Cr and Mn from their respective oxides because aluminium is more electropositive than Cr or Mn. The process of reduction is called alumino thermy.
`Cr_(2)O_(3) + 2Al to Al_(2)O_(3) + 2Cr`
`3Mn_(2)O_(4) + 8Al to 4Al_(2)O_(3) + 9Mn`
(d) Partial roasting of sulphide ore forms some oxide. The oxide then reduces the remaining sulphide ore into metal.
`2CuS + 3O_(2) to 2CuO + 2SO_(2)`
`2CuO + CuS to 3Cu^(+) + SO_(2)`
Promotional Banner

Topper's Solved these Questions

  • CHEMICAL ENERGETICS

    FIITJEE|Exercise ASSIGNMENT PROBLEMS (SECTION (I) JEE MAINS : SINGLE CORRECT OPTION)|92 Videos

  • CHEMICAL ENERGETICS

    FIITJEE|Exercise ASSIGNMENT PROBLEMS (SECTION (II) JEE ADVANCED WITH SINGLE CORRECT CHOICE)|84 Videos

  • CARBOXYLIC ACIDS AND ITS DERIVATIVES

    FIITJEE|Exercise SINGLE INTEGER ANSWER TYPE QUESTIONS|1 Videos

  • CHEMICAL EQUILIBRIUM

    FIITJEE|Exercise MATCHING TYPE QUESTIONS|3 Videos

Similar Questions

Explore conceptually related problems

Why is Zn but not copper used for the recovery of Ag from its cyanide complex [Ag(CN)_(2)]^(-)

STATEMENT-1 : Zince and not copper is used in the recovery of silver from the complex [Ag(CN)_(2)]^(-) and STATEMENT-2 : Zince is more powerful oxidising agent than copper.

Assertion : Zinc is used for the recovery of silver from the complex [Ag(CN)_(2)]^(-) Reason : Zinc is more electropositive than silver and is a better reducing agent.

Explain the following : (a) Aluminium vessel can be used to store conc HNO_(3) . (b) AlCl_(3) forms a dimer, but BCl_(3) does not. ( c) Al metal is frequency used as a reducing agent for the extraction of metal such as Cr , etc. (d) Al cannot be prepared by the electrolysis of aqueous solution of its salt. ( e) The B-X distance is shorter than what is expected theoretically in BX_(3) molecule (X = F, Cl, Br, I) . (f) Althrough the ionisation potential of B(8.30 eV) is less than gold (9.22 eV) , yet B is a non-metal while gold is a metal.

Answer the following questions briefly. (i) What is the actual reducing agent of haematite in blast furnace ? (ii) Give the equations for the recovery of lead from galena by air reduction. (iii) Why is sodium chloride added during electrolysis of fused anhydrous magnesium chloride. (iv) Zinc, not copper, is used for the recovery of metallic silver from the complex [Ag(CN)_(2)] . Explain. (v) Why is chalcocite roasted and not calcinated during recovery of copper ?