Chapter U2, Problem 8RE

Interpretation Introduction

Interpretation : Reason for table salt, NaCl, to not have a smell needs to be determined.

Concept Introduction :

Molecules smell differently. Humans are not able to smell all the molecules. Some molecules are small and some are large; some are polar and some are nonpolar. Some molecules have metallic bonding while some have ionic bonding. Some molecules are made of metals while some are made of nonmetals or both.

Answer to Problem 8RE

Correct answer:

B. It is an ionic compound.

Explanation of Solution

Reason for correct option:

Table salt, NaCl is made of a metal, sodium, and a nonmetal, chlorine. So it is an ionic compound. Molecules that have ionic bonding can exist only in solid state. These substances cannot easily form gases at room temperature. They cannot enter our nose and so cannot be detected by the receptor sites.

Conclusion

Reasons for incorrect options:

A.It is not made up of molecules- Table salt is a compound made up of molecules of NaCl. So this is an incorrect option.

C.No part of it enters the gas phase at room temperature- It cannot change to gas phase at any temperature as it is an ionic compound. So it cannot have smell.

D.All of the above- This option is incorrect as option A and option C are incorrect.

E.None of the above- This option is incorrect as option B is correct.