CUET Preparation Today
Which of the following is not correct? |
Acetone and chloroform form a solution with negative deviation from Raoult's law. \(HNO_3\) and \(H_2O\) from maximum boiling azeotrope at \(68\%\) \(HNO_3\) and \(32\%\) \(H_2O\) by mass composition. van't Hoff factor value for acetic acid = 2, when its concentration is \(0.1\) m and \(K_a = 1.8 × 10^{-6}\) Concentrations of isotonic solutions are same |
van't Hoff factor value for acetic acid = 2, when its concentration is \(0.1\) m and \(K_a = 1.8 × 10^{-6}\) |
The correct answer is option 3. van't Hoff factor value for acetic acid = 2, when its concentration is \(0.1\) m and \(K_a = 1.8 × 10^{-6}\). Let us evaluate each statement: 1. Acetone and chloroform form a solution with negative deviation from Raoult's law. This statement is true. Acetone and chloroform are two liquids that exhibit negative deviation from Raoult's law when mixed. This means that the vapor pressure of the mixture is lower than predicted by Raoult's law due to attractive forces between unlike molecules. 2. \(HNO_3\) and \(H_2O\) form maximum boiling azeotrope at \(68\%\) \(HNO_3\) and \(32\%\) \(H_2O\) by mass composition. This statement is correct. A maximum boiling azeotrope forms when the composition of the liquid and vapor phases are the same, resulting in the highest boiling point of the mixture. For \(HNO_3\) and \(H_2O\), a maximum boiling azeotrope occurs at approximately \(68\%\) \(HNO_3\) and \(32\%\) \(H_2O\) by mass composition. 3. van't Hoff factor value for acetic acid = 2, when its concentration is \(0.1\) m and \(K_a = 1.8 × 10^{-6}\) This statement seems incorrect. The van't Hoff factor (\(i\)) is the ratio of the observed concentration of solute particles to the concentration of solute as determined by a chemical formula. For acetic acid (\(CH_3COOH\)), which is a weak acid, it typically does not fully dissociate into ions in solution. Therefore, its van't Hoff factor is expected to be less than 2. However, the provided information about the concentration and \(K_a\) value doesn't directly determine the van't Hoff factor. This statement is correct. Isotonic solutions have the same concentration of solutes, which means they exert the same osmotic pressure and have the same tonicity. This property ensures that there is no net movement of water across a semipermeable membrane when cells are placed in an isotonic solution, maintaining cell volume and integrity. Thus the correct answer is option 3. van't Hoff factor value for acetic acid = 2, when its concentration is \(0.1\) m and \(K_a = 1.8 × 10^{-6}\) |
