<u>Answer:</u> The freezing point of solution is 2.6°C
<u>Explanation:</u>
To calculate the depression in freezing point, we use the equation:

Or,

where,
= 
Freezing point of pure solution = 5.5°C
i = Vant hoff factor = 1 (For non-electrolytes)
= molal freezing point depression constant = 5.12 K/m = 5.12 °C/m
= Given mass of solute (anthracene) = 7.99 g
= Molar mass of solute (anthracene) = 178.23 g/mol
= Mass of solvent (benzene) = 79 g
Putting values in above equation, we get:

Hence, the freezing point of solution is 2.6°C
In order to find out the ranking of ions basicity, check the
pKa values of each ions. The principle that you need to remember is that the
stronger the acid the weaker the corresponding conjugate base. The pKa dictates
acid value of the compound. The answer would be CH3NH, CH3O-, and CH3CH2-.
Answer:
The answer would be C, in both chemical and physical change, because everything is made up of matter. So if you have a chemical or physical change, that doesent change the total mass of your product ever.
Explanation: