Which among the following sets of compounds is used as raw material for the preparation of sodium carbonate by the Solvay process?

Correct order of density is

Sodium hydroxide is produced on a large scale:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R:$
Assertion $A:$ Metallic sodium dissolves in liquid ammonia giving a deep blue solution,which is paramagnetic.
Reason $R:$ The deep blue solution is due to the formation of amide.
In the light of the above statements,choose the correct answer from the options given below:

Give the preparation,properties,and uses of sodium chloride ($NaCl$ $-$ Rock salt).

As the atomic number increases,which of the following properties of alkali metals increases?