Final answer:
The TDS ratio, also known as the van 't Hoff factor, is calculated using the formula II = iMRT. To calculate the van 't Hoff factor, you need to determine the ratio of the observed osmotic pressure to the expected osmotic pressure and multiply this ratio by the number of ions per formula unit.
Step-by-step explanation:
The TDS ratio, also known as the van 't Hoff factor, is calculated using the formula II = iMRT. In this formula, 'II' represents the osmotic pressure, 'i' represents the van 't Hoff factor, 'M' represents the molarity of the solution, 'R' represents the ideal gas constant, and 'T' represents the temperature in Kelvin.
To calculate the van 't Hoff factor, you need to first determine the ratio of the observed osmotic pressure to the expected osmotic pressure. Then, multiply this ratio by the number of ions of solute per formula unit. This will give you the van 't Hoff factor.
For example, if the observed osmotic pressure is 2 atm and the expected osmotic pressure is 1 atm, and the solute has two ions per formula unit, the van 't Hoff factor would be 2.