What is caused by an excess of $Na^+$ in the human body?

$A$ mixture of lime paste is composed of sand,water,and which of the following?

Molten sodium is used in nuclear reactors to

Metallic magnesium is prepared by

What is obtained by the electrolysis of carnallite?

Assertion $A$: Alkali metals impart characteristic colors to the flame in the flame test.
Reason $R$: They have very low ionization enthalpy.