Sometimes it is possible to separate two sulphide ores by adjusting the proportion of oil to water or by using depressants. When a depressant $$NaCN$$ is added to an ore containing $$ZnS$$ and $$PbS,$$ what is the correct observation?
A.
$$NaCN$$ prevents $$PbS$$ from coming to the froth but allows $$ZnS$$ to come with froth.
B.
$$NaCN$$ prevents $$ZnS$$ from coming to the froth but allows $$PbS$$ to come with froth.
C.
$$NaCN$$ prevents frothing of both $$ZnS$$ and $$PbS,$$ hence no froth is formed.
D.
$$NaCN$$ does not act as depressant hence a mixture of $$PbS$$ and $$ZnS$$ is found in froth.
Answer :
$$NaCN$$ prevents $$ZnS$$ from coming to the froth but allows $$PbS$$ to come with froth.
Releted MCQ Question on Inorganic Chemistry >> Ores and Metallurgy