Which one of the following is a wrong statement about cast iron?

Extraction of silver is achieved by initial complexation of the ore (argentite) with $X$ followed by reduction with $Y$. $X$ and $Y$,respectively are

Roasted copper pyrite on smelting with sand produces

Which of the following is the correct chemical formula for slag?

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: The reduction of a metal oxide is easier if the metal formed is in liquid state than solid state.
Reason $R$: The value of $\Delta G^{\ominus}$ becomes more on negative side as entropy is higher in liquid state than solid state.
In the light of the above statements,choose the most appropriate answer from the options given below.

Furnaces are lined with $CaO$ because