Hydrated $AlCl_3$ is used as:

Select the correct statement regarding the following change:
$NO_2^+ \to NO_2 \to NO_2^-$

Baking powder used to make cake is a mixture of starch,$NaHCO_3$ and $Ca(H_2PO_4)_2$. The function of $Ca(H_2PO_4)_2$ is

The image formed by a convex mirror of focal length $30 \ cm$ is a quarter of the size of the object. The distance of the object from the mirror is $... \ cm$.

$A$ charge $q$ is placed at the centre of the line joining two equal charges $Q$. The system of the three charges will be in equilibrium if $q$ is equal to:

$A$ bullet of mass $2\, g$ has a charge of $2\, \mu C$. Through what potential difference must it be accelerated,starting from rest,to acquire a speed of $10\, m/s$?