The compound formed on heating sodium metal in a current of dry ammonia gas is

What is the primary purpose of the Dow's process?

What are the metal ions present in carnallite?

$A$ compound $(M_2O_2)$ of group $I$ element $(M)$ hydrolyses to form $M^{+}$,$OH^{-}$ and $X$. Another compound $(M'O_2)$ of group $I$ element $(M')$ hydrolyses to form $(M')^{+}$,$OH^{-}$,$X$ and $Y$. What are $X$ and $Y$ respectively?

$X$ $\xrightarrow{N_2, \Delta} Y$ $\xrightarrow{H_2O} Z$ (colourless gas) $\xrightarrow{CuSO_4} T$ (blue colour)
Then,substances $Y$ and $T$ are

The metal mainly used in devising photoelectric cells is: