Properties Of Solids And Liquids Question 105
Question: It is known that wax contracts on solidification. If molten wax is taken in a large vessel and it is allowed to cool slowly, then [CBSE PMT 1994]
Options:
A) It will start solidifying from the top downward
B) It will start solidifying from the bottom upward
C) It will start solidifying from the middle, upward and downward at equal rates
D) The whole mass will solidify simultaneously
Show Answer
Answer:
Correct Answer: B
Solution:
Substances are classified into two categories (i)
water like substances which expand on solidification. (ii)
CO2 like (Wax, Ghee etc.) which contract on solidification.
Their behaviour regarding solidification is opposite.
Melting point of ice decreases with rise of temp but that of wax etc increases with increase in temperature.
Similarly ice starts forming from top downwards whereas wax starts its formation from bottom.
