Which of the following can be used to extinguish a fire caused by alkali metals?

Two capacitors of capacities $1 \mu F$ and $C \mu F$ are connected in series and the combination is charged to a potential difference of $120 \ V$. If the charge on the combination is $80 \mu C$,the energy stored in the capacitor of capacity $C$ in $\mu J$ is

Which of the following will release hydrogen gas upon reaction with hydrochloric acid?

$A$ capacitor of capacity $4 \mu F$ is charged to $80 \ V$ and another capacitor of capacity $6 \mu F$ is charged to $30 \ V$. When they are connected,the energy lost by the $4 \mu F$ capacitor is: (in $mJ$)

Which one of the following is not a micronutrient?

Considering only the Principal values of inverse functions,the set $A = \{x \geq 0 \mid \tan^{-1}(2x) + \tan^{-1}(3x) = \frac{\pi}{4}\}$