Question

Sahil took a white solid from his teacher to find out its melting point. During the
experiment, he found that the melting point was 160° C. But, the teacher told him that actual melting point of the solid
is 150° C. What could be the reason for Sahil's observation?

(A) Melting point of a solid depends upon the procedure and the amount taken.
(B) Solids can have different melting points depending upon the method of storage.
(C) The solid contains some impurities mixed with the pure compound.
(D)If solid is heated strongly, the melting point increases ​

Answer 1

Answer:

OPTION C

Explanation:

Because melting point of a substance or a compound increases with the addition of impurities.

Answer 2

Answer:

The correct option is (C) The solid contains some impurities mixed with the pure compound.

Explanation:

• Impure substances tend to alter the orderly pattern, in the solid, of forces acting upon the particles that keep them intact.
• The impurities also cause the lattice of the solid to get destabilized.
• This variation of forces of attraction leads to a change in melting point.
• Some forces maybe weaken rather quickly when little energy is applied, while others may need much more energy to break down the forces.
• This causes the substance's melting point range to increase.

Conclusion:

The solid contains some impurities mixed with the pure compound.