In which cell is the free energy of a chemical reaction directly converted into electricity?

What are anode and cathode?

What is the density of a solution of sulphuric acid used as an electrolyte in lead accumulators (in $g \ mL^{-1}$)?

Match List-$I$ with List-$II$.

$LIST$-$I$ (Cell)	$LIST$-$II$ (Use/Property/Reaction)
$A$. Leclanche cell	$I$. Converts energy of combustion into electrical energy
$B$. Ni-Cd cell	$II$. Does not involve any ion in solution and is used in hearing aids
$C$. Fuel cell	$III$. Rechargeable
$D$. Mercury cell	$IV$. Reaction at anode $Zn \rightarrow Zn^{2+} + 2e^-$

Choose the correct answer from the options given below:

In the cell represented as $Ni_{(s)}|Ni_{(1M)}^{2+}||Ag_{(1M)}^{+}|Ag_{(s)}$,the reducing agent is

Which of the following net cell reactions occurs in a galvanic cell containing a cadmium electrode and a standard hydrogen electrode? Given: $E^0(Cd^{2+}(aq)|Cd(s)) = -0.403 \text{ V}$.