Question

Marjorie is trying to determine the identity of an unknown substance. After running tests, she determines that the substance is insoluble in CCl4 with a density of about 2.2 g/mL. Substance Density Boiling Point Solubility (in water) Solubility (in CCl4) NaCl 2.165 g/mL 1413°C soluble insoluble C10H8 1.14 g/mL 255°C insoluble soluble FeCl3 2.898 g/mL 315°C soluble insoluble SiO2 2.634 g/mL 2590°C insoluble insoluble Using the data above, which of the following substances is most likely Marjorie's unknown? A. FeCl3 B. NaCl C. SiO2 D. C10H8

Answer 1

Answer:
The substance is most likely NaCl.

Step-by-step explanation:
Solubility:
As stated in statement the substance is insoluble in CCl₄ (Tetrachloromethane), it shows that the substance is polar in nature. In given options only C₁₀H₈ is soluble in CCl₄ because both are non polar in nature and like dissolves like. Hence, C₁₀H₈ is rejected.

Density:
Now, we are left with three options. NaCl, FeCl₃ and SiO₂. The student found that the density of substance is 2.20 g.mL⁻¹. Which is very close to the density of NaCl (i.e. 2.165 g.mL⁻¹). Therefore, most probably the substance the student is dealing with is Sodium Chloride.