chemistry solution of chapter 2 solution

1. 37. The boiling point of a 0.2 m solution of a non-
electrolyte in water is
(Kb for water = 0.52 K kg mor1
)
(a) 100 °C (b) 100.52°C
(c) 100.104°C (d) 100.26 °C ~
(Term I, 2021-22)

2. V • - .. -.- - ., ✓ :
4 ;) j IJ I~orijlU<,O!;t•, c6• I1
✓,06 (M,>lar ma'/~s 180g rn<JI~
1
, ;
• is dl~i,,,lv,•d i11 1 kg of w;Jt<.:r In a saua: p:m. At what :
tomporatur<"• will thh !,olution boil'!
(Kt, for water - 0.52 K kg mol 1
, boiling point of pure ;
wntc;,r <DI 3/:J. 15 K) (Delhi 2013i .
(3 rrtnrk~)
43. Calt ulatc tf ,e boiling p0int elevation for a solution
' prepared by addir,g 10 g of CaCl2 to 200 g of water.
(Kb for water = 0,52 K kg moi-1
, molar mass of CaC1
2
"" 111 g moi-
1
) (315,Al 2017C, Foreign 2014)
.
.
.

3. 4o. Calculate the freezing point of a solution containing
' 60 g of glucose (molar mass = 180 g moi-1
) in 250 g
of water. (K,of water= 1.86 K kg mo,-1
) (2018)
47. Calculate the mass of compound (molar mass = 256
g mol-1
) to be dissolved in 75 g of benzene to lower
its freezing point by 0.48 K. (Kt= 5.12 K kg mol-1
).
(Delhi 2014)

4. 45. Nisha took two aqueous solutions - one containing
7.5 g of urea (Molar mass = 60 g/mol) and the other
containing 42.75 g of substance Z in 100 g of water,
respectively. It was observed that both the solutions
froze at the same temperature. Calculate the moar
mass of Z. (2020) ~~

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· 50.
Calculate the mass of ascorbic acid (Molar m9ss =
176 g moi-
1
) to be dissolved in 75 g of acetic acid, to
lower its freezing point by 1.5°C .
(K, = 3.9 K kg mor1
) (NCERT lntext, 2020)
A 4% solution (w/w) of sucrose (M = 342 g mor1
)
in water has a freezing point of 271.15 K. Calculate
t he freezing point of 5% glucose (M = 180 g mol-1
)
in water. (Given : Freezing point of pure water
= 273.15 K) (Delhi 2019) ~

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A 10% solution (by mass) of sucrose in water has
freezing point of 269.15 K. Calculate the freezing
point of 10% glucose in water, if freezing point of
pure water is 273.15 K.
(Given : Molar mass of sucrose = 342 g moi-1,
molar mass of glucose= 180 g moi-1) (Delhi 2017) (Ev)
.l

8. I
4. 1.00 g of a non-electrolyte solute dissolved in 50 g l.
of benzene lowered the freezing point of benzene !
I
by 0.40 K. The freezing point depression constant of l
benzene is 5.12 K kg moi-1. Find the molar mass of j
I
the solute. (Al 2013) ~
55. A 5% solution (by mass) of cane-sugar in water has
freezing point of 271 K. Calculate the freezingpoint
of 5% solution (by mass) of glucose in water if the
freezing point of pure water is 273.15 K.
[Molecular masses : Glucose C6H120 6 : 180 amu;
Cane-sugar Ci2H22O11 : 342 amu]
(NCER
T, 3/5, Al 2013C) ~
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9. 62. For a 5% solution of urea (Molar mass = 60 g/
' mol), calculate the osmotic pressure at 300 K.
[R= 0.0821 LatmK-1
mor1
] (2020)

10. 72. Calculate the boiling point of solution when 4 g of
MgS04 (M = 120 g mol-1
) was dissolved in 100 g !
of water, assuming Mg504 undergoes complet e ;
ionization. i
(Kb for water= 0.52 K kg mol-1
) (Al 2016) !
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11. -- - ---- --· ---------- -
73. Assuming complete dissociation, calculate the
expected freezing point of a solution prepared by
dissolving 6.00 g of Glauber's salt, Na2SO4·10H2O in
0.100 kg of water. ·
(Kr for water = 1.86 K kg mor1, atomic masses :
Na = 23, S = 32, 0 = 16, H = 1) (215, Al 2014C) ~ :
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12. - ~.. -l•'z.-..en 195 g of F-CH2 -COOH (molar mass
== 7B g mo1-1
J is dissolved in 500 g of water, the
~~~$On in freezing point is observed to be
~~-- C~lculat~ the degree of dissociation of
~ - r_:,.:~-C(>OH.
~
r.;,'f~, ; ~, tor water =-
,.; 1.86 K kg mo1-1
]
(3/ 5, 2020) ~

13. - - , - - - ._ - • • - - • • - • • , ■ ' ■ 'O . I I " ' I '
76. A 0.01 m aqueous solution of AICl3 freezes at
- 0.068 °C. Calculate the percentage of dissociation.
[Given : K, tor water_
= 1.86 K kg mor1
1 (2020) (E~ ·

14. .
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: 76. A 0.01 m aqueous solution of AICl3 freezes at
: -0.068 °C. Calculate the percentage of dissociation.
f [Given: K,tor water= 1.86 K kg mor1
] (2020) (EvJ
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77. Calculate the freezing point of solution when 1.9
.g of MgCl2 (M = 95 g moi-1
) was dissolved in 50
g of water, assuming MgCl2 undergoes complete
ionization.
{Kt for water = 1.86 K kg mor
1
) (Delhi 2016)

15. --------·
----- _
._ - --- -
81. A solution contains 5.85 g NaCl (Molar mass =
58.5 g mol-1
) per litre of solution. It has an osmotic
pressure of 4.75 atm at 27°C. Calculate the degree
of dissociation of NaCl in this solution.
(Given : R= 0.082 L atm K-1 moi-1) (3/5,2020)

16. ----______:_----- ---------
~4. Calculate the molarity of 9.8% (w/W) solution of
H
2
S0
4
if the density of the solution is 1.02 g mL
1
.
(Molar mass of H2504 = 98 g mor
1
)
(2/5, Foreign 2014) ~

17. -- -- - - ---- - -
6. A tmlution of gh,co~f:1 (mobJr ma§(j e 180 g mor1} in
watftr i5 lijf,ellt1<i :1s jJJ% (by masg). What would bo
tt1c rn1.,lality and molarity of thesolution?
(Density of solution "" 1.2g·
mL-1
)
(NCERT, t3
/5,Al 2014, 2013)
... ..

18. 7. An unknown gas 'X' is dissolved in water at 2.5 bar
pressure and has mole fraction 0.04 in solution. The
mole fraction of 'X' gas when the pressure of gas is
doubled at the same temperature is
(a) 0.08 (b) 0.04 (c) 0.02 (d) 0.92
(Term I, 2021-22) ~

19. -=:,:tJJ- ,.__. ••n,n • --,
:4.. Tr:e partial pressure of ethane over a saturated
soM ion containing 6.56 x 10-2
g of ethane is 1 bar.
~ the solution contains 5.0 x 10-2
g of ethane, then
14il.at will be the partialpressure of the gas?
(NCERT, Delhi 2013C, Al2012C) @