Explanation
(a) The boiling point of a liquid is the temperature at which its s.v.p is equal to the external atmospheric pressure.
(b) Experiment to determine the boiling point of a small quantity of a liquid.

Some liquid is introduced into the shorter length of the J - tube above the mercury. The beaker and its contents are heated and stirred continuously. At a stage when the levels of mercury in the two limbs of the J - tube are the same the temperature is read. At this temperature the s.v.p. of the liquid is equal to the atmospheric pressure. This temperature is the boiling point of the liquid.
(c) Heat lost by copper = Heat gained by water
\(mc \theta = m_{1} c_{1} \theta_{1} + ml\)
\(0.3 \times 400 \times (950° - 100°) = 0.25 \times 4200 \times (100° - 25°) + 2.26 \times 10^{6} M\)
\(M = \frac{102000 - 78750}{2.26 \times 10^{6}}\)
\(M = 10.3g\)
Therefore, the mass of water that will boil away is 10.3g.
(d) Four effects of heat other than expansion are:
(1) Change of state (2) Change in temperature (3) Chemical change (4) Change in electrical resistance of conductivity. (5) Melting sublimation.

