Each student in Ms. Major's class was given an unknown substance. Ms. Major gave her students a list, shown below, of substances and their properties to help them identify their unknown.

Question

Substance Density Boiling Point Appearance
Water 1.0 g/mL 100°C colorless liquid
Ethanol 0.789 g/mL 78.4°C colorless liquid
Sodium Hydroxide 2.13 g/mL 1388°C white solid
Phosphoric Acid 1.685 g/mL 158°C white solid or colorless liquid

If a student's unknown is a white solid and its density was calculated to be about 1.7 g/mL, it is most likely _______.
A.
sodium hydroxide
B.
ethanol
C.
water
D.
phosphoric acid

Answer 1

Given the information provided, if a student's unknown is a white solid with a density calculated to be about 1.7 g/mL, it is most likely D. phosphoric acid.

This is because phosphoric acid has a density of 1.685 g/mL and can appear as a white solid or a colorless liquid, fitting the description of the unknown substance. Sodium hydroxide, while also a white solid, has a significantly higher density of 2.13 g/mL, which does not match the student's density measurement.