Question

A spoon is kept in contact with ice cubes for sometimes. Later the same spoon was held over the flame of a candle. The figure shows the observation. What do you infer from the figure?

A. Spoon is an inflammable substances
B. Burning of candle is a spontaneous process
C. $CO_2$ is a product of combustion
D. Water vapour is a product of combustion

Answer 1

Hint: Vaporisation: It is defined as the phenomena of transition of compound from its liquid state to vapour state on excessive heating above the boiling point of the element. It is of two types: boiling which is a bulk process and evaporation which is a surface process.

Complete step by step answer:
Combustion: It is defined as the process by which the substances get heated up in the presence of oxygen to give off product in the form of heat and the heat generated is used in the reaction to give off the final product. The necessary condition for the combustion reaction is the presence of oxygen.
Analysis of the picture to make the conclusion about the process that has taken place:
If we analyse the figure we will see that when a spoon is kept on the flame, the water vapours are formed. This is because when the spoon is kept in contact with an ice cube, the cooling of ice is passed on to the spoon and the spoon becomes cold due to the conduction of heat from ice to the end attached to it to the other end, till the entire spoon has the same temperature.
When this cooled spoon is heated the evaporation of water from the surface of the spoon occurs in which liquid on the spoon undergoes transition to form water vapours.

Thus the correct option is D, since we analysed that the vaporisation is taking place in this process.



Note:
Spoon which is made up of steel substance is a good conductor of heat and electricity both. The conduction of heat from ice to spoon made it cool and when its temperature was increased on heating, the phase transition occurred for the substance on the element without changing the state of the steel spoon.