iii. State one condition to ensure that the deposit is smooth, firm and long lasting.

iv. Write the reaction taking place at the cathode.

v. Write the reaction taking place at the anode.

The sketch below illustrates the refining of aluminium by Hoopes process.

i. Which of A and B is the cathode and which one is the anode?

ii. What is the electrolyte in the tank?

iii. What material is used for the cathode?

State the property of the metal being utilised in the following:

Use of metal	Property
Zinc in galvanisation
Aluminium in thermite welding

i. A gas cylinder contains ``24 \times 10^{24}`` molecules of nitrogen gas. If Avogadro.s number is
``6 \times10^{23}`` and the relative atomic mass of nitrogen is 14, calculate:
1. Mass of nitrogen gas in the cylinder.
2. Volume of nitrogen at STP in ``\pu{dm3}``.

ii. Commercial sodium hydroxide weighing ``\pu{30 g}`` has some sodium chloride in it. The
mixture on dissolving in water and subsequent treatment with excess silver nitrate
solution formed a precipitate weighing ``\pu{14.3 g}``. What is the percentage of sodium
chloride in the commercial sample of sodium hydroxide? The equation for the
reaction is
$$\ce{NaCl + AgNO3 . AgCl + NaNO3 }$$.
[Relative molecular mass of NaCl = 58; AgCl = 143]

iii. A certain gas .X. occupies a volume of ``\pu{100 cm3}`` at STP and weighs 0.5 g. Find its
relative molecular mass.

Solution A is a strong acid.
Solution B is a weak acid.
Solution C is a strong alkali.

i. Which solution contains solute molecules in addition to water molecules?