Two elements $A$ and $B$ form compounds of formula $AB_2$ and $AB_4$. When dissolved in $20.0\, g$ of benzene $1.0 \,g$ of $AB_2$ lowers f. pt. by 2.3$^{\circ}$C whereas $1.0\, g$ of $AB_4$ lowers f. pt. by 1.3$^{\circ}$C. The $K_f$ for benzene is $5.1$. The atomic masses of $A$ and $B$ are
- 25, 42
- 42, 25
- 52, 48
- 48, 52
The Correct Option is A
Solution and Explanation
Top Questions on Colligative Properties
- Mass of glucose (\(C_6H_{12}O_6\)) required to be dissolved to prepare one litre of its solution which is isotonic with \(15 \, \text{g L}^{-1}\) solution of urea (\(NH_2CONH_2\)) is:
{Given:} Molar mass in \(\text{g mol}^{-1}\): \[ C : 12, \, H : 1, \, O : 16, \, N : 14 \]- NEET (UG) - 2024
- Chemistry
- Colligative Properties
- An artificial cell is made by encapsulating \(0.2 \, \text{M}\) glucose solution within a semipermeable membrane. The osmotic pressure developed when the artificial cell is placed within a \(0.05 \, \text{M}\) solution of NaCl at 300 K is ______ \( \times 10^{-1} \, \text{bar} \). (Nearest Integer)
Given: \(R = 0.083 \, \text{L bar mol}^{-1} \text{K}^{-1}\)
Assume complete dissociation of NaCl.- JEE Main - 2024
- Chemistry
- Colligative Properties
- Consider the dissociation of the weak acid HX as given below:
\[\text{HX(aq)} \rightleftharpoons \text{H}^+(\text{aq}) + \text{X}^-(\text{aq}), \, K_a = 1.2 \times 10^{-5}\]
\([K_a: \text{dissociation constant}]\)
The osmotic pressure of \(0.03 \, \text{M}\) aqueous solution of HX at 300 K is ______ \( \times 10^{-2} \, \text{bar} \) (nearest integer).
Given: \(R = 0.083 \, \text{L bar mol}^{-1} \text{K}^{-1}\)- JEE Main - 2024
- Chemistry
- Colligative Properties
- Considering acetic acid dissociates in water, its dissociation constant is $6.25 \times 10^{-5}$. If 5 mL of acetic acid is dissolved in 1 litre water, the solution will freeze at $-x \times 10^{-1}$ °C, provided pure water freezes at 0 °C. $x = $ _____ (Nearest integer)
Given: $(K_f)_{water} = 1.86$ K kg mol$^{-1}$
density of acetic acid is 1.2 g mol$^{-1}$
molar mass of water = 18 g mol$^{-1}$
molar mass of acetic acid = 60 g mol$^{-1}$
density of water = 1 g cm$^{-3}$
Acetic acid dissociates as CH$_3$COOH $\rightleftharpoons$ CH$_3$COO$^-$ + H$^+$- JEE Main - 2024
- Chemistry
- Colligative Properties
- A solution containing \(10 \, \text{g}\) of an electrolyte \(AB_2\) in \(100 \, \text{g}\) of water boils at \(100.52^\circ \text{C}\). The degree of ionization of the electrolyte (\(\alpha\)) is _____ \(\times 10^{-1}\). (nearest integer)
\([ \text{Given: Molar mass of } AB_2 = 200 \, \text{g mol}^{-1}, \, K_b \, (\text{molal boiling point elevation const. of water}) = 0.52 \, \text{K kg mol}^{-1}, \text{ boiling point of water} = 100^\circ \text{C}; \, AB_2 \text{ ionises as } AB_2 \rightarrow A^{2+} + 2B^- ]\)- JEE Main - 2024
- Chemistry
- Colligative Properties
Questions Asked in AIIMS exam
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : 02 is liberated in the non-cyclic photophosphorylation.
Reason (R) : Liberation of oxygen is due to photolysis of water.
In the light of the above statements, choose the correct answer from the options given below
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Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : The Cro-Magnon man was the direct ancestor of the living modern man.
Reason (R) : Cro-Magnon man had slightly prognathous face.
In the light of the above statements, choose the correct answer from the options given below
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- Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion: Orbit of a satellite is within the gravitational field of earth whereas escaping is beyond the gravitational field of earth.
Reason: Orbital velocity of a satellite is greater than its escape velocity.
In the light of the above statements, choose the correct answer from the options given below- AIIMS - 2019
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Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : In eukaryotes, transcription occurs in nucleus.
Reason (R) : In bacteria, transcription and translation occurs in cytoplasm.
In the light of the above statements, choose the correct answer from the options given below
- AIIMS - 2019
- Transcription
Concepts Used:
Colligative Properties
Colligative Property of any substance is entirely dependent on the ratio of the number of solute particles to the total number of solvent particles but does not depend on the nature of particles. There are four colligative properties: vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure.
Examples of Colligative Properties
We can notice the colligative properties of arrangements by going through the accompanying examples:
- On the off chance that we add a spot of salt to a glass full of water, its freezing temperature is brought down impressively than its normal temperature. On the other hand, the boiling temperature is likewise increased and the arrangement will have a lower vapor pressure. There are also changes observed in its osmotic pressure.
- In the same way, if we add alcohol to water, the solution’s freezing point goes down below the normal temperature that is usually observed for either pure alcohol or water.
Types of Colligative Properties
- Freezing point depression: ΔTf =1000 x kf x m2 /(M2 x m1)
- Boiling point elevation: ΔTb = kb m
- Osmotic pressure: π = (n2/V) RT
- Relative lowering of vapor pressure: (Po - Ps)/Po