$A$ metal that exists as a liquid at room temperature is obtained by heating its sulphide in the presence of air. Identify the metal and its ore and give the reaction involved.

(N/A) Mercury is the only metal that exists as a liquid at room temperature. It is obtained from its sulphide ore,known as cinnabar $(HgS)$,by heating it in the presence of air (roasting).
The chemical reactions involved are as follows:
$1$. Heating cinnabar in air to form mercury$(II)$ oxide:
$2HgS + 3O_2 \xrightarrow{\text{Heat}} 2HgO + 2SO_2$
$2$. Further heating of mercury$(II)$ oxide to obtain mercury metal:
$2HgO \xrightarrow{\text{Heat}} 2Hg + O_2$