The process of industrial manufacturing of sodium carbonate is known as

When $CO$ is passed over solid $NaOH$ heated to $200\,^{\circ}C$,it forms

Among the following,the number of metals that can be used as electrodes in a photoelectric cell is $.......$ (Integer answer)
$A. Li$
$B. Na$
$C. Rb$
$D. Cs$

In cement composition,the main compound (by percentage) is?

Metallic magnesium is prepared by

Which cannot be used to generate $H_{2}$?