Given below are two statements : One is labelled as Assertion A and the other labelled as reason R

Assertion A : During the boiling of water having temporary hardness, Mg(HCO₃)₂ is converted to MgCO₃.

Reason R : The solubility product of Mg(OH)₂ is greater than that of MgCO₃.

In the light of the above statements, choose the most appropriate answer from the options given below :

The number of ionisable hydrogens present in the product obtained from a reaction of phosphorus trichloride and phosphonic acid is :

In a binary compound, atoms of element A form a hcp structure and those of element M occupy 2/3 of the tetrahedral voids of the hcp structure. The formula of the binary compound is :

The chemical that is added to reduce the melting point of the reaction mixture during the extraction of aluminium is :