Question:
The mixture which shows negative deviation from Raoult's law is:
The mixture which shows negative deviation from Raoult's law is:
Show Hint
Negative deviation occurs when strong specific interactions like hydrogen bonding form between components (e.g., acetone + chloroform, HNO$_3$ + H$_2$O).
Updated On: Jun 12, 2026
- \( (\text{CH}_3)_2\text{CO} + \text{CHCl}_3 \)
- \( \text{C}_2\text{H}_5\text{OH} + (\text{CH}_3)_2\text{CO} \)
- \( \text{C}_6\text{H}_6 + \text{C}_6\text{H}_5(\text{CH}_3) \)
- \( \text{C}_2\text{H}_5\text{Cl} + \text{C}_2\text{H}_5\text{Br} \)
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Concept:
Raoult’s law describes ideal liquid solutions where intermolecular forces between unlike molecules (A–B) are equal to those between like molecules (A–A and B–B).
Deviations occur when:
• Negative deviation: A–B interactions are stronger than A–A and B–B interactions.
• Positive deviation: A–B interactions are weaker than A–A and B–B interactions. Stronger A–B interactions reduce escaping tendency of molecules, thereby lowering vapour pressure → negative deviation.
Step 1: Identify the mixture showing strong intermolecular attraction. We examine the interaction between acetone and chloroform: \[ (\text{CH}_3)_2\text{CO} \quad \text{and} \quad \text{CHCl}_3 \] Acetone contains a highly electronegative oxygen atom with lone pairs, making it a strong hydrogen bond acceptor. Chloroform has an acidic hydrogen due to the strong electron-withdrawing effect of three chlorine atoms. Thus, strong hydrogen bonding is formed: \[ \text{CHCl}_3 \cdots O=C(\text{CH}_3)_2 \] This strong A–B interaction is stronger than the self-interactions in the pure liquids.
Step 2: Conclusion for Option (1). Due to strong hydrogen bonding between acetone and chloroform, the mixture shows reduced vapour pressure and hence negative deviation from Raoult’s law. \[ \boxed{\text{Option (1) is correct}} \]
Step 3: Analysis of other options.
• Option (2): Ethanol + acetone Ethanol has strong intermolecular hydrogen bonding. Mixing with acetone disrupts ethanol–ethanol hydrogen bonding, leading to weaker A–B interactions → positive deviation.
• Option (3): Benzene + toluene Both are non-polar and have similar intermolecular forces → behaves as an ideal solution.
• Option (4): Ethyl chloride + ethyl bromide Similar molecular structure and similar intermolecular forces → approximately an ideal solution.
• Negative deviation: A–B interactions are stronger than A–A and B–B interactions.
• Positive deviation: A–B interactions are weaker than A–A and B–B interactions. Stronger A–B interactions reduce escaping tendency of molecules, thereby lowering vapour pressure → negative deviation.
Step 1: Identify the mixture showing strong intermolecular attraction. We examine the interaction between acetone and chloroform: \[ (\text{CH}_3)_2\text{CO} \quad \text{and} \quad \text{CHCl}_3 \] Acetone contains a highly electronegative oxygen atom with lone pairs, making it a strong hydrogen bond acceptor. Chloroform has an acidic hydrogen due to the strong electron-withdrawing effect of three chlorine atoms. Thus, strong hydrogen bonding is formed: \[ \text{CHCl}_3 \cdots O=C(\text{CH}_3)_2 \] This strong A–B interaction is stronger than the self-interactions in the pure liquids.
Step 2: Conclusion for Option (1). Due to strong hydrogen bonding between acetone and chloroform, the mixture shows reduced vapour pressure and hence negative deviation from Raoult’s law. \[ \boxed{\text{Option (1) is correct}} \]
Step 3: Analysis of other options.
• Option (2): Ethanol + acetone Ethanol has strong intermolecular hydrogen bonding. Mixing with acetone disrupts ethanol–ethanol hydrogen bonding, leading to weaker A–B interactions → positive deviation.
• Option (3): Benzene + toluene Both are non-polar and have similar intermolecular forces → behaves as an ideal solution.
• Option (4): Ethyl chloride + ethyl bromide Similar molecular structure and similar intermolecular forces → approximately an ideal solution.
Was this answer helpful?
0
0
Top TS EAMCET Chemistry Questions
- A, B and C are three biomolecules. The results of the tests performed on them are given below :A, B and C are respectively :
Molisch's lest Barfoed Test Biuret Test A Positive Negative Negativde B Positive Positive Negative C Negative Negative Positive - 1 mole of $H_2$ and 2 moles of $I_2$ are taken initially in a 2 litre vessel. The number of moles of $H_2$ at equilibrium is 0.2. Then the number of moles of $I_2$ and HI at equilibrium is
- The pH of a buffer containing equal molarconcentration of a weak base and its chloride ( $K_b$ for weak base = $2 \times 10^{-5}$, log 2 = 0.3) is
- Atomic radius (pm) of Al, Si, N and F respectively is
- Consider the following electrode process of a cell, $ {Cl^{-1} -> \frac{1}{2} Cl_2 + e^{-}}$ $ {[MCl + e^{-} -> M + Cl^{-} ] }$ If EMF of this cell is $-1.140\, V$ and $E^0$ value of the cell is $-0.55\,V$ at $298\,K$, the value of the equilibrium constant of the sparingly soluble salt MCl is in the order of
View More Questions
Top TS EAMCET Solutions Questions
- The volume of $O_2$ (in L) that can be produced at STP by heating 112 g of $ {KClO_3}$ is approximately (Molar mass of $ {KCIO_3 = 122.6 \, g \, mol^{-1}}$)
- Calculate the normality of a solution obtained on mixing 100 ml of $\frac{M}{10} H_2 SO_4 , 50 \, ml$ of $\frac{N}{2} HNO_3$ and $25 \, ml $ of $\frac{N}{5} HCl$ solutions.
At 50 °C, the vapour pressure of pure benzene is 268 torr. The number of moles of non-volatile solute per mole of benzene required to prepare a solution having a vapour pressure of 167 torr at the same temperature is
- At 300 K, the vapour pressure of liquids A and B are 600 and 500 mm of Hg respectively. Two moles of A and three moles of B are mixed. The mole fractions of A and B in vapor state are respectively
- Identify the major product \((P)\) in the following reaction sequence: \[ (\text{CH}_3)_3\text{CBr} \xrightarrow[\Delta]{\text{Alcoholic KOH}} X \xrightarrow{\text{HBr}} P \]
View More Questions
Top TS EAMCET Questions
- A bag contains $5$ red balls, $3$ black balls and $4$ white balls are drawn at random. The probability that they are not of same colour is
- If $cosec\, \theta - \cot \theta = 2017$, then quadrant in which $\theta $ lies is
- If $a$ is a unit vector, then $| a \times \hat{ i }|^{2}+| a \times \hat{ j }|^{2}+| a \times \hat{ k }|^{2}=$
- $A$ straight line makes an intercept on the $Y$-axis twice as long as that on $X$-axis and is at a unit distance from the origin. Then the line is represented by the equations
- Let $S$ and $S'$ be the foci of an ellipse and B be one end of its minor axis. If $SBS'$ is an isosceles right angled triangle then the eccentricity of the ellipse is
View More Questions