Question

6. A substance X is such a state that can flow easily and
attains the shape of container in which it is kept. On adding
copper sulphate solution in it, the solution turns into cyan
(blue) colour. If the substance X is cooled suddenly, it gets
converted into substance Y which as definite volume and
shape. On heating the substance Y more, it gets converted
into substance z. The substance Z does not have difinite
volume or shape. Answer the following questions based on
this information:
(1) Give the names of substances X, Y and Z.
(2) State the name of process of conversion of substance
X into substance Y and the necessary temperature.​

Answer 1

i)the names of substances X, Y and Z are X - water , Y- ice , Z - steam    ;    and the process of conversion is freezing at 0°C

ii) X is water because in water the inter molecular distance is much due to which it can flow easily and take the shape of any container , Y is ice as it is a solid and the molecules are closely packed so it has a definite shape and volume , Z is steam where the molecules have a large inter molecular distance and have very low van der waal's force so it doesn't have a definite shape and volume

iii) X which is water can be converted into Y by using freezing at 0 °C , as it causes the internal energy to decrease and brings the molecules closer causing a liquid to change into solid.