Melting Point

Question 1

1. The purity of the compound is confirmed by ____________
   a) Its melting point and boiling point
   b) Chromatographic technique
   c) Spectroscopy
   d) All of the mentioned

Answer 1

d) All of the mentioned

Question 2

Select the correct statement from the following options.
a) The transformation of solid to liquid is called melting and the reverse process is called freezing
b) The transformation of solid to liquid is called freezing and the reverse process is called melting
c) The transformation of liquid to solid is called melting and the reverse process is called freezing
d) None of the mentioned

Answer 2

a) The transformation of solid to liquid is called melting and the reverse process is called freezing

Question 3

The temperature at which solid and liquid coexist in equilibrium is called ____________
a) Melting point of liquid
b) Freezing point of liquid
c) Freezing point of solid
d) All of the mentioned

Answer 3

b) Freezing point of liquid

Question 4

Select the incorrect statement from the following option.
a) Every pure solid crystalline substance has a characteristic and unique melting point
b) Impure sample of substance has different melting point
c) Two different pure substances have same melting points
d) Melting point serves as the criteria of purity of a solid substance

Answer 4

c) Two different pure substances have same melting points

Question 5

When the solid and liquid phase are in equilibrium, the temperature ____________
a) Increases gradually
b) Decreases gradually
c) Remains constant
d) None of the mentioned

Answer 5

c) Remains constant

Question 6

The melting point of ice is ____________
a) 0 degC
b) 100 degC
c) 4 degC
d) -4 degC

Answer 6

a) 0 degC

Question 7

Molar heat of fusion is defined as ____________
a) Energy required to melt one gram of solid
b) Energy required to melt one mole of solid
c) Energy required to melt one kilogram of solid d) Energy required to melt ten moles of solid

Answer 7

b) Energy required to melt one mole of solid

Question 8

The temperature remains constant during phase change because the increased kinetic energy is used to overcome the cohesive forces in the liquid.
a) True
b) False

Answer 8

a) True

Question 9

What is the molar heat of fusion (kJ/mol) of water?
a) 1.3
b) 0.84
c) 7.61
d) 6.01

Answer 9

d) 6.01

Question 10

What is the melting point of mercury?
a) 357 degC
b) -39 degC
c) 0 degC
d) 100 degC

Answer 10

-39 degC