The compound which does not exist is

Which of the following is $NOT$ present in baking powder?

Which of the following reactions does not liberate a gaseous product?

Write the chemical reactions for the formation of oxides,peroxides,and superoxides of alkali metals.

Given below are two statements:
Statement $I$ : The $4f$ and $5f$-series of elements are placed separately in the Periodic table to preserve the principle of classification.
Statement $II$ : $S$-block elements can be found in pure form in nature.
In the light of the above statements,choose the most appropriate answer from the options given below :

Sodium is produced by the electrolysis of a molten mixture of about $40\%$ $NaCl$ and $60\%$ $CaCl_2$ because