2.A solution of 10g of an electrolyte AB2 in 100g of water balls at 100.52 degree Celsius of ionization of electrolyte(α) ___________×10-2
[Given: molar mass of AB2=200g/mol , Kp(molal boiling point elevation constant ) =0.52KKg/mol, boiling point of water 100 degree Celsius, AB2 ionises as AB2+-----> A2+ +2B- ] Jee main 2024
Answer. 5
3. When 'x' ×10-2ml methanol (molar mass=32g , density=0.792g/cm3) is added to 100ml .Water (density 1g/cm3), the following diagram is obtained.
x= ________ (nearest integer). Jee main 2024
Answer. 543
4. Considering acetic acid dissociates in water, its dissociation constant is If 6.25×10-5. If 5ml of acetic acid is dissolved in 1 litre water, the solution will freeze at -x×10-2 degree celcius provided pure water freezes at 0 degree celcius.
x= _________. (Nearest integer)
Kf(water)= 1.86KKg/mol
density of acetic acid is 1.2g/ml
molar mass of water = 18g
molar mass of acetic acid = 60g
density of water = 1g/cm3
Acetic acid dissociates as CH3COOH ⇌ CH3COOH- + H+
Answer. 19
5. An artificial cell is made by encapsulating 0.2M glucose solution within a semipermeable membrane. The osmotic pressure developed when the artificial cell is placed within a solution of NaCl at 300K is ________ ×10-1 bar. (nearest integer). Jee main 2024
Given : R=0.083Lbar/molK
Assume complete dissociation of NaCl
Answer. 25
6. 2.7kg of each of water and acetic acid are mixed. The freezing point of the solution will be -x degree celcius . Consider the acetic acid does not dimerise in water, nor dissociates in water. x= ________ (nearest integer) Jee main 2024
Given:
Molar mass of water = 18g
acetic acid = 60g
Kf of water= 1.86KKg/mol
Kf of acetic acid = 3.90KKg/mol
freezing point: H2O = 273K , acetic acid = 290K
Answer. 31
7. 2.5g of a non-volatile, non-electrolyte is dissolved in 100g of water at 25 degree celcius .The solution showed a boiling point elevation by 2 degree celcius . Assuming the solute concentration is negligible with respect to the solvent concentration, the vapor pressure of the resulting aqueous solution is _________mm of hg . (nearest integer) Jee main 2024
Given:
1 atm pressure = 760 mm of hg , molar mass of water = 18g
Answer. 707
8. Mass of ethylene glycol (antifreeze) to be added to 18.6kg of water to protect the freezing point at -24 degree celcius is ________ kg . (Molar mass in g/mol for ethylene glycol 62 ,Kf of water = 1.86KKg/mol ) Jee main 2024
Answer. 15
9. The osmotic pressure of a dilute solution is 7×10⁵ Pa at 273K. Osmotic pressure of the same solution
at 283K is _________ ×104N/m Jee main 2024
Answer. 73
10. 0.05M CuSO4 when treated with 0.01M K2Cr2O7 gives green colour solution of Cu2Cr207. The two solutions are seperated as shown below: [SPM: Semi permeable membrane]. Jee main 2024
Due to osmosis:
(a)Molarity of K2Cr2O7 solution is lowered .
(b)Green colour formation observed on side Y.
(c)Molarity of CuSO4 solution is lowered.
(d)Green colour formation observed on side X.
Answer. (c)Molarity of CuSO4 solution is lowered.
Osmosis leads to the net movement of water molecule from low osmotic pressure to high osmotic pressure. Since the iM value of 0.05M CuSO4 solution is higher hence it has higher osmotic pressure so the water moves towards CuSO4 solution leads to drop of its molarity. The solute molecules do not cross S.P.M. via osmosis.
11. We have three aqueous solutions of NaCl labelled as A,B and C with concentration 0.1M , 0.01M and 0.001M respectively. The value of vant' hoff factor(i) for the solutions will be in the order:
Jee main 2024
(a) iA<iB<iC
(b) iA<iB<iC
(c) iA>iB>iC
(d) iA=iB=iC
Answer. (b) iA<iB<iC
12. Identify the mixture that shows positive deviations from Raoult's law. Jee main 2024
(a) (CH3)2CO + CS2
(b) (CH3)2CO + C6H5NH2
(c) CHCl3 + C6H6
(d) CH3Cl + (CH3)2CO
Answer. (a)(CH3)2CO + CS2
13. The solution from the following with highest depression in freezing point/ lowering freezing point is. Jee main 2024
(a) 180 gram of Acetic Acid dissolved in Benzene
(b) 180 gram of Acetic Acid dissolved in water
(c) 180 gram of benzoic acid dissolved in Benzene
(d) 180 gram of glucose dissolved in water
Answer. (b) 180 gram of Acetic Acid dissolved in water
In the following options acetic acid only dissolved and dissociate in water.
14. What happens to freezing point of benzene when small quantity of naphthalene is added to benzene ? Jee main 2024
(a) Increases
(b) decreases
(c) remains unchanged
(d) first decreases and then increases
Answer. (b) decreases
On addition of naphthalene to benzene there is depression in freezing point of benzene.
15. A solution of two miscible liquids show negative division from Raolt's law will have:
Jee main 2024
(a) Increased vapour pressure, increased boiling point
(b) increased vapour pressure, decreased boiling point
(c) decreased vapour pressure, decreased boiling point
(d) decreased vapour pressure, increased boiling point
Answer. (d) decreased vapour pressure, increased boiling point
Negative Deviation from Raoult's Law
periodicity