Short Answer TypeGive balanced chemical equations for the following reactions:
(i) Fluorine is passed through cold, dilute NaOH solution.
(ii) Hydrogen peroxide is treated with acidified KMnO4 solution.
(iii) Sulphuric acid is treated with hydrogen sulphide.
Draw the structure of xenon tetrafluoride molecule and state the hybridization of the central atom and the geometry of the molecule.
Name the important ore of silver. Write all the steps and reactions involved in the Cyanide process for the extraction of silver from its ore.
Argentite ( silver glance), Ag2S or Horn silver.
Concentration – The sulphide ore is crushed, powdered and then concentrated by the
Froth flotation process.
Treatment with sodium cyanide.
The concentrated ore is agitated with dilute solution of NaCN in the presence of air. When soluble sodium argentocyanide is obtained.
Ag2S + 4 NaCN ⇌ 2 Na[Ag(CN)2] + Na2S
Na2S + 2O2 → Na2SO4
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Ag2S + 4 NaCN + 2O2 → 2 Na[Ag(CN)2] + Na2SO4
Precipitation of silver
2Na[Ag(CN)2] + Zn → Na2[Zn(CN)4] + 2 Ag ↓
Silver thus obtained is in the form of dark amorphous mass. Fusion
The precipitated silver is filtered, pressed, dried and fused with borax when a bright Compact mass is obtained.
Electrolytic refining process
Silver thus obtained usually contain impurities of Zn, Cu and gold.
Thin sheet of pure silver – cathode
A block of impure silver – anode
K[Ag(CN)2] or a solution of silver nitrate containing 1% HNO3 is used as a electrolyte.
On passing electricity pure silver gets deposited on the cathode
Explain the following:
(i) Why do transition metal ions possess a great tendency to form complexes?
(ii) The paramagnetic character in 3d-transition series elements increases up to Mn and
then decreases.
How can the following conversions be brought about:
(i) Glycerol to formic acid
(ii) Chlorobenzene to phenol
(iii) Diethyl ether to ethanol
(iv) Phenol to aniline.
(i) How is iodoform prepared from ethanol? Give balanced equation.
(ii) What will be the product formed when chlorobenzene is heated with sodium metal in the presence of dry ether?
Give balanced equations for the following name reactions:
(i) Reimer-Tiemann reaction.
(ii) Rosenmund reaction
(iii) Hoffmann’s degradation reaction
Give one chemical test to distinguish between the following pairs of compounds:
(i) Ethylamine and diethylamine.
(ii) Acetaldehyde and benzaldehyde
Arrange the following compounds in the ascending order of their basic strength and give reasons for your answer:
Methylamine, Aniline, Ethylamine, Diethyl ether
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