Q15 of 26 Page 1

(i) Name the method of refining to obtain low boiling metal like mercury.

(ii) What is the role of pine oil in froth floatation process?


(iii) Reduction of metal oxide to metal becomes easier if the metal obtained is in liquid state. Why?


(i) The method of refining to obtain low boiling metal like Hg, Zn, Cd is distillation. On evaporating, pure metal distills over and then collected.


(ii) Role of pine oil in froth floatation is that it acts as froth collector. Froth carries mineral particles to surface while the impurities settle down. The froth is then skimmed off.



(iii) The entropy of a metal is higher in its liquid state than in its solid state. If ΔS is positive, on increasing the temperature (T), the value of TΔS would increase (ΔH < TΔS) and then ΔG will become negative and the reaction becomes feasible.


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13

Differentiate between the following:

(i) Solution and Colloid


(ii) Homogeneous catalysis and Heterogeneous catalysis


(iii) O/W emulsion and W/O emulsion


 14

A solution is prepared by dissolving 5 g of non-volatile solute in 95 g of water. It has a vapour pressure of 23.375 mm Hg at 25°C. Calculate the molar mass of the solute. (Vapour pressure of pure water at 25°C is 23.75 mm Hg)

 16

Examine the given defective crystal:


Answer the following questions:


(i) Is the above defect stoichiometric or non-stoichiometric?


(ii) Write the term used for this type of defect.


(iii) Why do silver halides show this type of defect?


 17

Predict the products of the following reactions: