Question 1 1 / -0
A 0.100 m solution of NaClO3 freezes at – 0.343o C. At 0.001 m concentration of the same salt, the electrical interferences between the ions no longer exist, because on an average, the ions are too far from each other.
Question 2 1 / -0
Raoult’s law states that for a solution of volatile liquids the partial pressure of each component in the solution is
Solution
Raoult’s law states that for a solution of volatile liquids the partial pressure of each component in the solution is directly proportional to mole fraction of component.
Question 3 1 / -0
The molality of a solute in a solution is the
Question 4 1 / -0
Molality of a solution relates the
Solution
Molality is number of moles of solute dissolved in per Kg of solvent.
Question 5 1 / -0
A solution of sucrose in 100 g of water boils at 100.25°C. If this solution is boiled till its temperature becomes 101°C, the mass of water evaporated from the solution is
Question 6 1 / -0
Example of solution of liquid in gas is
Solution
Solute is water (liquid) and solvent is gas( air).
Question 7 1 / -0
Which of the following is true?
Question 8 1 / -0
Which of the following is true?
Question 9 1 / -0
An aqueous solution of an ionic salt having molality equal to 0.1892 freezes at – 0.704o C. What is the van't Hoff factor of the salt? (Given Kf for water = 1.86 K/m)
Question 10 1 / -0
Which of the following is not a colligative property?
Question 11 1 / -0
The freezing point of equimolal solution will be the lowest for
Question 12 1 / -0
At a certain temperature, the vapour pressures of benzene and toluene are 119 torr and 37 torr, respectively. The mole fraction of toluene in the vapour phase, which is in equilibrium with a solution of benzene and toluene in 1 : 1 molar ratio, is
Question 13 1 / -0
The expression relating molarity of a solution with its molality is (where the various symbols have their usual meanings)
Question 14 1 / -0
The vapour pressures of pure benzene and toluene are 160 Torr and 60 Torr, respectively. The mole fraction of benzene in vapour phase in contact with equimolar solution of benzene and toluene would be
Question 15 1 / -0
A non-ideal solution was prepared by mixing 30 ml chloroform and 50 ml acetone. The volume of the mixture will be
Question 16 1 / -0
The boiling point of a solution at a height of 10 km above the sea level is
Question 17 1 / -0
The expression to compute the molar mass of a solute from the elevation of boiling point of a solvent is (where the various symbols have their usual meanings)
Question 18 1 / -0
The osmotic pressure of 0.1 M sodium chloride solution at 27°C is
Question 19 1 / -0
Which law shows relation between pressure and solubility of a gas in solvent
Solution
Henry’s Law states that as the partial pressure of gas increases over liquid solubility of gas also increases.
Question 20 1 / -0
For a dilute solution, Raoult`s law states that
Question 21 1 / -0
Minimum boiling azeotrope is form by the solution which show
Solution
Positively deviated non ideal solution forms Minimum boiling Point azeotropes.
Question 22 1 / -0
Which of the following statements is not true about ideal solutions?
Question 23 1 / -0
Which of the following solutions will show positive deviation from ideal behaviour?
Question 24 1 / -0
The vapour pressure lowering of a solvent is proportional to
Question 25 1 / -0
In the phenomenon of osmosis through semi-permeable membrane,
Question 26 1 / -0
The ratio of the value of any colligative property for $$Ba{Cl}_{2}$$ solution to that for urea solution under similar condition is:
Solution
The ratio of the value of any colligative property for $$Ba{Cl}_{2}$$ solution of urea solution under similar conditions is $$3:1$$.
1 molecule of $$Ba{Cl}_{2}$$ dissociates to give 3 ions.
$$Ba{Cl}_{2} \rightarrow Ba^{2+}+2Cl^-$$
Hence, the van't Hoff factor 'i' for $$Ba{Cl}_{2}$$ is 3.
Urea is non-electrolyte and hence does not dissociate.
Hence, the van't Hoff factor 'i' for urea is 1.
The ratio of the value of any colligative property for $$Ba{Cl}_{2}$$ solution of urea solution under similar conditions is equal to the ratio of the values of the vant Hoff factor 'i' for $$Ba{Cl}_{2}$$ and urea.
Option B is correct.
Question 27 1 / -0
The van't Hoff factor for a solute which does not dissociate or associate in solution is:
Solution
The Van't Hoff factor for a solute which does not dissociate or associate in solution is 1 as it is non-electrolyte.
Question 28 1 / -0
Among $$0.1\:M$$ solutions of $$NaCl,\:CaCl_2\:and\:Al_2(SO)_3$$, the one with highest vapour pressure is:
Solution
Colligative properties : Those physical properties of a solution which depend upon the number of particles in a given volume of the solution or the mole fraction of the solute are called colligative properties.
The following four properties are colligative properties : (i)Lowering of vapour pressure of the solvent. (ii)Elevation in boiling point of the solvent. (iii)Depression in freezing point of solvent. (iv)Osmotic pressure.
As no of ions increases, lowering of VP increases,
here,
NaCl = 2 ion
$$CaCl_2$$ = 3 ion
and $$Al_2(SO_4)_3$$ = 5 ions so
NaCl will give highest VP.
Question 29 1 / -0
A $$0.1\:molar$$ solution of $$NaCl$$ is found to be isotonic with $$1\%$$ urea solution. Calculate
Solution
$$NaCl (1-x)$$ dissociates into $$Na^{+}(x)$$ and $$Cl^{-}(x)$$
Total concentration in solution $$= c(1+x) = 0.1 M (1+x)$$
Osmotic pressure of $$NaCl$$ solution $$= 0.1 M (1+x) RT$$
Osmotic pressure of urea solution $$= \dfrac{(1/60)mol }{0.1 L} RT$$
since solutions are isotonic, therefore, $$1+x = 1.667$$
(b) Degree of dissociation $$= x = 0.667$$
Question 30 1 / -0
The boiling point of $$C_{6}H_{6},\:CH_{3}OH,\:C_{6}H_{5}NH_{2}$$ and $$C_{6}H_{5}NO_{2}$$ are $$80\ ^{\circ}C$$, $$65\ ^{\circ}C$$, $$184\ ^{\circ}C$$ $$212\ ^{\circ}C$$ respectively.
Which will show the highest vapour pressure at room temperature?
Solution
Lower the boiling point higher is the vapour pressure.
Methanol $$\displaystyle CH_3OH$$ with a lowest boiling point will show highest vapour pressure at room temperature as it is most volatile.
Hence, the correct option is $$B$$
Question 31 1 / -0
At $$20^0C$$, 36 g of sodium chloride can be dissolved in 100 g water. At $$80^0C$$, how many grams of sodium chloride can be dissolved in 100 g of water?
Solution
From the solubility table, it is evident that at $$20^oC$$ the solubility of $$NaCl$$ is 36 while from $$60-80^oC$$ the solubility of $$NaCl$$ is 37 gm.
Question 32 1 / -0
A solution of benzene and toluene is an example of ________ solution.
Solution
Due to absence of polarity, benzene and toluene dont have any interaction forces so they dont show any deviation and forms ideal solutions.
Question 33 1 / -0
In which of the following solvents, should $$KBr$$ be soluble at $$25^{\circ}C$$ ($$D$$ is the dielectric constant)?
Solution
Like dissolves like. Since $$KBr$$ is a polar ionic compound, it will be soluble in a polar solvent. The solvent with a higher value of dielectric constant will provide maximum solubility. It will be most soluble in polar solvents, i.e. with the highest value of $$D$$.
Question 34 1 / -0
The Van't Hoff factor of sulphur solution is _________ .
Solution
The Van't Hoff factor of sulphur solution is $$1 = \dfrac{1}{8}.$$ $$\displaystyle 8S \rightleftharpoons S_8$$ $$\displaystyle i = \frac {\text {Actual number of particles}}{\text {Number of particles before association}}=\frac {1}{8}$$
Question 35 1 / -0
The Vant Hoff factor (i) for a dilute solution of $$K_{3}[Fe(CN)_{6}]$$ is (Assuming $$100\%$$ ionsation):
Solution
The Vant Hoff factor (i) for a dilute solution of $$K_3[Fe(CN)_6]$$ is $$4$$. It dissociates to give $$3$$ potassium ions and $$1\:[Fe(CN)_6] ^{3-}$$ ion.
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