Generally,metals are solid in nature. Which one of the following metals is found in liquid state at room temperature?

$(a)$ $A$ substance $X$,an oxide of a metal,is used extensively in the cement industry. This element is found in our bones also. On treatment with water,it forms a solution which turns red litmus blue. Identify $X$ and also write the chemical reaction involved.
$(b)$ Choose a metal from the following metals which reacts only with hot water: Sodium,magnesium,iron. Mention the products formed during the reaction.

What is an alloy called if one of the metals is $Mercury$?

What is the process of extracting a metal from its ore and obtaining it in a pure form called?

Which of the following is a reducing agent?

Which metal oxide cannot be reduced by carbon?