Answer 1 - hypotonic is 0.9% NaCl, hypertonic is distilled water, isotonic is 6% NaCl

You: This is incorrect. The word ‘hypo’ means low, I remember from my older sister, who is studying to become a doctor, uses the word hypotension a lot… It means low blood pressure. Therefore, the word ‘hyper’ mean high.

Prof. Smith: Well done! A very nice way to remember the terms! 

You: Therefore, hypotonic is lower concentration of solute and hypertonic is higher concentration of solute. But the word ‘iso’ means the same, so isotonic solution is the same concentration of solute.

Which is the correct answer here?

Answer 2:

hypotonic is distilled water, hypertonic is 6% NaCl, isotonic is 0.9% NaCl

Answer 3:

hypotonic is 6% NaCl, hypertonic is 0.9% NaCl, isotonic is distilled water