Free Solved Choose the answer which presents the chemical formulas for two substances in order of decreasing melting point (highest melting point first) and gives a valid reason for this order.


It is asked in the question that the order of decreasing melting point.
Choose the answer which presents the chemical formulas for two substances in order of decreasing melting point (highest melting point first) and gives a valid reason for this order.

a) SiO2 > SeO2 due ionic bonding in SiO2 but not in SeO2.
b) Kr > Ar because of the greater atomic mass and stronger dispersion forces of Kr.
c) HOCl > LiCl due to hydrogen-bonding forces in HOCl not present in LiCl.
d) CO > C(diamond) because of the layered molecular structure of CO.
e) SiF4 > Si due to the higher charge on silicon in SiF4.

Sol: Step 1 of 2
Given data: a) SiO2>SeO2 due ionic bonding in SiO2 but not in SeO2.
b) Kr>Ar because of the greater atomic mass and stronger dispersion forces of Kr.
c) HOCl>LiCl due to hydrogen-bonding forces in HOCl not present in LiCl.
d) CO>C(diamond) because of the layered molecular structure of CO.
e) SiF4>Si due to the higher charge on silicon in SiF4.

Find: which substance has highest melting point.
Explanation:
This method involves placing the sample in a capillary tube and running an experiment that will heat the sample until it reaches the melting point.

Step 2 of 2
SiF4>Si due to the higher charge on silicon in SiF4.
The reason for this order is that SiF4 has a higher melting point compared to Si. In SiF4, silicon is bonded to four fluorine atoms, resulting in a higher charge on the silicon atom. This higher charge leads to stronger electrostatic forces of attraction between the silicon and fluorine atoms, making it more difficult to break the bonds and thus requiring a higher temperature to melt.

On the other hand, Si consists of a network of covalent bonds between silicon atoms. While these covalent bonds are strong, they are not as strong as the ionic bonds in SiF4.
Explanation:
Therefore, Si has a lower melting point compared to SiF4.

Final solution
It is important to consider the types of bonds and the strength of those bonds when comparing the melting points of substances. In this case, the higher charge and stronger electrostatic forces in SiF4 result in a higher melting point compared to Si.

Therefore, option (e) that is SiF4>Si due to the higher charge on silicon in SiF4 is correct.
So these are the order of decreasing melting point which is given above.

There are Concept of melting point which is given below

See video:

 

 

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