While extracting an element from its ore, the ore is grind and leached with dil KCN solution to form the soluble product potassium argentocyanide. The element isA. MnB. CrC. FeD. Ag

While extracting an element from its ore, the ore is grind and leached

1.	While extracting an element from its ore, the ore is grind and leached with dil KCN solution to form the soluble product potassium argentocyanide. The element isA. MnB. CrC. FeD. Ag
Answer» Correct Answer - D Silver is obtained form its low grade ores by leaching them whith a dulute solution of sodium cyanide, when the silver compounds dissolve forming the soluble complex argentocyanide ion: `Ag_(2)S + 4 NaCNhArr2Na [Ag (CN)_(2)] + Na_(2)S` Air is blown into the mixture to oxidize the sodium sulphide to sulphate and thereby make the reversible reaction proceed completely to the right. `4 Na_(2)S + 5O_(2) + 2H_(2)O rarr 2 Na_(2)SO_(4) + NaOH + 2S` The silver is precipitated form the solution by adding some electropositive metal, usually Zn or AI: `2Na [Ag(CN)_(2)] + Zn rarr 2 Ag + Na_(2) [Zn(CN)_(4)]`

Discussion

No Comment Found

Related InterviewSolutions

Which of the following d-block element has half - filled penultimate as well as valence subshell ?A. CuB. AuC. AgD. Cr
General configuration of outermost and penultimate shell is `(n - 1) s^(2) (n - 1) p^(6) (n - 1)d^(x) ns^(2)`. If `n = 4` and `x = 5` then no. of protons in the nucleus will beA. `gt 25`B. `lt 24`C. 25D. 30
Statement-1: The highest oxidation state of chromium in its compound is +6. Statement-2: Chromium atom has only six electrons in ns and `(n-1)d` orbitals.A. If both assertion and reason are true and reason is the correct explanation of assertion.B. If both assertion and reason are true and reason not is the correct explanation of assertion.C. If assertion is trun but reason is false.D. If both assertion and reason are false.
Assertion: Transitio metals show variable valence. Reason : Due to a large energy difference bteween the `ns^(2)` and `(n - 1)d` electrons.A. If both assetion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are ture but reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true.
Oh heating pyrolusite with `KOH` in presence of air we getA. `KMnO_(4)`B. `K_(2) MnO_(4)`C. `Mn (OH)_(2)`D. `Mn_(3) O_(4)`
The colour of `K_(2)Cr_(2)O_(7)` changes from red-orange to lemon-yellow on treatment with `KOH_((aq.))`, because of:A. The reduction of `Cr^(VI)` to `Cr^(III)`B. The formation of chromium hydroxidedC. The conversion of dichromate to chromateD. The oxidation of potassium hydroxide to potassium peroxide
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective verticalcolumns. Give special emphasis on the following points: (i) electronic configurations (ii) oxidation states (iii) ionisation enthalpies and (iv) atomic sizes.
Describe the oxidising action of potassium dichromate and write the ionic equations of reaction with: (i). Iodide (ii). Iron (II) solution and (III). `H_2S`
Describe the preparation of potassium dichromate from iron chromite ore.What is the effect of increasing pH on a solution of potassium dichromate?
The transition elements have a general electronic configuration:A. `ns^(2) np^(6) nd^(1 - 10)`B. `(n - 1) d^(1 - 10) ns^(0 -2) np^(0 -6)`C. `(n - 1) d^(1 - 10) ns^(1 -2)`D. None of these

While extracting an element from its ore, the ore is grind and leached with dil KCN solution to form the soluble product potassium argentocyanide. The element isA. MnB. CrC. FeD. Ag

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment