General Princip...

An ore of tin containing, $$FeCrO_4$$ is concentrated by:

Forth floatation process of concentration is based on the:

Lithopone is a mixture of zinc sulphide and barium sulphate. It is used as a paint instead of white lead, because it:

For which of the following ores forth floatation method is used for concentration?

Study the Ellingham diagram for the formation of some oxides and answer the following question.
At the point of intersection of $$Al_2O_3$$ and $$MgO$$ curves (A), $$\triangle G^0$$ becomes zero for the reaction,

     $$\frac{2}{3}Al_2O_3+2Mg \rightarrow + \frac{4}{3} Al$$

Below this point, magnesium can reduce alumina. Although thermodynamically feasible, Al is not used for reduction of $$MgO$$ because:

Sometimes it is possible to separate two sulphide ores by adjusting the proportion of oil to water by using depressants. When a depressant $$NaCN$$ is added to an ore containing $$ZnS$$ and $$PbS$$, what is the correct observation?

From the Ellingham graph between Gibb's energy and temperature, out of $$C$$ and $$CO$$ which is a better reducing agent for $$ZnO$$?

During the formation of the slag by the reaction of flux and impurities which of the following is an example of acidic and basic flux?
(i) $$FeO + SiO_2\rightarrow FeSiO_3$$
(ii) $$SiO_2+MgO\rightarrow MgO\rightarrow MgSiO_3$$

The reaction $$Cr_2O_3+2Al\rightarrow Al_2O_3+2Cr(\triangle G^0 = -421 kJ) $$ is thermodynamically feasible due to -ve value of $$\triangle G.$$ Why does this reaction not take place at room temperature?

Sulphides ores are converted to oxides before reduction. This is explained on the basis of which of the following?