1. 15g of methyl alcohol is present in 100 mL of solution.
If the
density of solution is 0.96 g mL, calculate the mass
percentage of methyl alcohol in solution.
[Ans, 15625%] 14,
2, A solution is prepared by dis_olving 15 g of cane sugar in 60 g
water. Compute the mass per cent of each component of soution.
[Ans, Mass percentage of sugar 20%, Mass percentage of water 15.
80%]
3. The density of the solution ofa salt X is L.15 gmL.20 mL of
the solution when completely evaporated gave a residue of
4.6 g of the salt. Calculate the mass percentage of the solut in
solution.
[Ans. 20%]
4. (a) 5.85 g of NaClis dissolved in 200 mL of water. What will
be the molarity of this solution?
[Ans. 0.5 M)
(b) Calculate the molarity of the solution obtained by
dissolving 20.6 g NaBr in 500 mL of water.
[Ans. 0.4 M 16.
S. The density ofa solution containing 40% by mass of HCI is
1.2 g/mL. Calculate the molarity of the solution.
[Ans, 13.15 M]
6. Concentrated sulphuric acid has density of 1.9 g/m and 99%
H,SO, by mass. Calculate the molarity of the acid. 17.
[Ans, 19.19 M)
7. A mixture of alcohol and water contains 54% water by mass.
Calculate the mole fraction of alcohol in this solution.
[Ans. 0.25]
8. What amount of oxalic acid is required to prepare 250 mL
0.1 N soution (Given: molecular mass of oxalic acid = 126)?
LAns. i.575 g]
9. 7.45 g of potassium chloride is dissolved in 100 g of water.
What will be the molality of the solution?
[Ans. 1m]
10. Asolution is prepared. by mixing 50 g sugar in 100 g of water
at 25° C.Calculate the following:
18.
(i)) Mass per cent of water.
(ii) Mole fraction of sugar.
(iiü) Molality of the solution.
[Ans. (i) 66.6 (i) 0.0256 (iii) 1.46 m]
1. A solution contains 25% water, 50% ethanoic acid and 25%
ethanol by mass. Compute the mole fraction of cach 19.
component:
[Ans. Mole fraction of water = 0.5022;
Mole fraction of ethanoic acid 0.3013;
Mole fraction of ethanol = 0.1965] 20.
21.
13. Calculate the final molarity when 2.0 litre of 3.0 M sugar
solution and 3.0 litre of 2.5 M sugar solution are mixed and
then diluted to 10 litres with water.
[Hnt; After mixing number of moles of sugar present
-13.5
=2x3+3x2.5 =13.5; Final molarity =1.35 M]
10
14, If20.0 mLof 1.0 Mcalcium chloride and 60 mL of 0.2 MCaCl,
are míxed, what will be the molarity of the final solution?
[Ans. 0.40 M)
15. Calculate the molarity of each of the ions in a solution when
3.0 litre of 4.0 MNaCl and 4.0 litre of 2.0 MCoCl, are mixed
and diluted to 10 litre.
[Ans. Molarity Na =12 M; Molarity Co* =0.8 M; Molarity
CI = 2.8 M]
[Hint: NaCl = Na + CI
l mole Imole Imole
3x4 mole 12 mole 12 mole
CoCl, = Co* + 2CI :
1mole 1 mole 2 mole
2x4 mole 8 mole 16 mole
Total CI ions = 28 mole]
16, What volume of 96% H,SO, solution (density 1.83 gm.) is
required to prepare 4 litre of 3.0 M H,SO, solution?
[Ans. 670mL]
Hint: First determine the molarity of 96% H,SO, and then
dilute to get the desired solution.]
17, Calculate the molarity of each ion in solution after 2.0litre of
3.0 M AgNO, is mixed with 3.0 litre of 1.0 MBaCl,.
[Ans. Molarity of Ba =0.6 M; Molarity of NO, =1.2 M]
[Hint: BaCl, + 2AgNO, = 2AgCl J. + Ba(NO3)2
Initial 3 mole 6 mole 6 mole Ag will react
Ba2+ Ag with 6 mole C1 to form
6 mole CI 6 mole AgCl(s)
NO,,
After 3 mole 6 mole
reaction Ba2+ NO,
Total volume 3.0+ 2.0 =5 litre.]
18. The density of a 10.0% by mass of KCl solution in water is
1.06 g/mL. Calculate molarity, molality and mole fraction of
KCl in this solution.
[Ams. Molarity =1.42 M; Molality =1.489 m; mole fraction of
KCl=0.026]
19. Calculate the molality and mole fraction of the solute in an
aqueous solution containing 6 g of urea per 500 g of water
(Mol. mass of ürea = 60).
[Ans. Molality =0.2 M; Mole fraction =0.00359]
20. Calculate the molality of I litre solution of 93% H, SO,
(mass/volume). The density of the solution is 1.84 g/mL.
(MLNR 1993)
[Ans. 10,428 m]
21. Molarity of H,SO, is 0.8 and its density is 1.06 glcm'. What
will be its concentration in terms of molality and mole
fraction. (CBSE (Mains) 2005]
[Ans. m= 0814; xH, so, = 0.014 ]
