Q14 of 26 Page 1

(i) Indicate the principle behind the method used for the refining of Nickel.

(ii) What is then role of dilute NaCN in extraction of Gold?


(iii) What is ‘copper matte’?


(i)Nickel is refined using the technique vapor phase refining. In this method the metal which is converted to its volatile compound is decomposed to give pure metal.


(ii)NaCN is used in the process of Leaching. Leaching is used if the ore is soluble in a suitable solvent. It helps in oxidation of the metal. (Au → Au+)


More from this chapter

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12

Write the names and structures of the monomers of the following polymers:

(i) Terylene


(ii) Bakelite


(iii) Buna-S


 13

(i) Which one of the following is a monosaccharide:

Starch, maltose, fructose, cellulose


(ii) What is the difference between acidic amino acids and basic amino acids?


(iii) Write the name of the vitamin whose deficiency causes bleeding of gums.


 15

Calculate the emf of the following cell at 250C:

Zn|Zn2+(0.001 M) || H+(0.01 M) | H2(g)(1 bar) | Pt(s)


2E0(zn2+/Zn) = -0.76 V, E0(H+/H ) = 0.00 V


 16

Give reasons for the following observations:

(i) A delta is formed at the meeting point of sea water and river water.


(ii) NH3 gas adsorbs more readily than N2 gas on the surface of charcoal.


(iii) Powdered substances are more effective adsorbents.