Among the following compounds,the number of those present in copper matte is $......$
$A.$ $CuCO_3$
$B.$ $Cu_2S$
$C.$ $Cu_2O$
$D.$ $FeO$

Which of the following is not a basic flux?

Blister copper is ..........

Match List-$I$ (substances) with List-$II$ (processes) employed in the manufacture of the substances and select the correct option.

List-$I$ (Substances)	List-$II$ (Processes)
$A$. Sulphuric acid	$i$. Haber's process
$B$. Steel	$ii$. Bessemer's process
$C$. Sodium hydroxide	$iii$. Leblanc process
$D$. Ammonia	$iv$. Contact process

The percentage $(\%)$ of silver in the alloy German silver is:

Given below are two statements related to Ellingham diagram:
Statement-$I$ : Ellingham diagrams can be constructed for formation of oxides,sulfides and halides of metals.
Statement-$II$ : It consists of plots of $\Delta_f H^0$ vs $T$ for formation of oxides of elements.
In the light of the above statements,choose the most appropriate answer from the options given below: