Solutions(11th And 12th > Chemistry ) Questions and Answers
Explanation:-
Answer: Option B. -> In a solution showing negative deviation from Raoult's law A-B type of molecular interactions are stronger than A-A and B-B type of molecular interactions.:
B
a) △Hmix > 0, △ V mix > 0 are true for mixtures showing positive deviations from Raoult's law only. Hence option (a) is incorrect
b) It is true
c) Nitric acid and water forms intermolecular H-bonding. Hence shows Negative deviation from Raoult's law.
d) Azeotropes are of two types – minimum and maximum boiling azeotropes. Only minimum boiling Azeotrope boils at temperature below the boiling temperature of its constituents. Hence option (d) is incorrect.
Explanation:-
Answer: Option A. -> Osmotic pressure:
A
Only Osmotic pressure is a colligative property.
‘Relative lowering of vapour pressure of the solvent’ is a colligative property but not only vapour pressure. Similar argument for boiling point and freezing point
In an experiment on depression of freezing point, two beakers leveled as A and B were filled with 1000 g. of water each. 40 g and 80 g of a certain non-electrolytic solute were added to both the beakers and freezing point of the solutions were noted as TfA and TfB respectively. Now both the solutions were poured into an empty beaker C and the freezing point of the mixed solution is found to be TfC . What is the ratio TfA : TfB : TfC?
Explanation:-
Answer: Option B. -> 2 : 4 : 3:
B
△Tf=Kf m
⇒0−Tf=Kf m
⇒=−Kf m
If 40 g of solute contains 'x'~moles of it then 80 g of the solut ill contains '2x' moles of it
mA=xWt.of solvent in g1000=x10001000=x
mB=2xWt.of solvent in g1000=x10001000=2x
mC=3xWt.of solvent in g1000=3x10001000=1.5x
Required ration TfA:TfB:Tfc=1.2:1.5=2:4:3
Explanation:-
Answer: Option B. -> 0.1 M Na3 PO4:
B
Depression in vapor pressure is a colligative property. More the no. of particles present in the solution lower will be the vapor pressure. consists of maximum ions hence it show lowest vapour pressure.
MoleculeNaClNa3Po4BaCl2SucroseNo. of ions per molecule1+1 = 23+1 = 41+2 = 31
Explanation:-
Answer: Option C. -> 1+2α:
C
Na2SO41−α⇌2Na+2α+SO2−4α
Total no. of ions after dissociation = 1+2α
vant Hoff's factor, i=No.of particles after dissociationNo.of particles before dissociation=1+2α
Explanation:-
Answer: Option A. -> 348.8:
A
Isotonic solutions have same osmotic pressure
As Osmotic pressure = C R T
⇒ C1=C2
⇒ n1V1=n2V2
5% W/W solution means 100g of solution contains 5 g of solute
∴ 8.6601=5M1001000
⇒ M=5×60×108.6=348.8