A solution of sucrose (molar mass = 342 g mol-1) has been prepared by dissolving 68.5 g of sucrose in 1000 g of water. The freezing point of the solution obtained will be (kf for water = 1.86 K kg mol-1)
-0.372o C
-0.520o C
+0.372o C
+0.372o C
A.
-0.372o C
Depression in freezing point,
A 0.0020 m aqueous solution of an ionic compound Co(NH3)5(NO2)Cl freezes at -0.00732o C . Number of moles of ions which 1 mol of ionic compound produces on being dissolved in water will be (kf = - 1.86o C/m)
2
3
4
4
A.
2
Given,
molality = 0.0020 m
Δ Tf = 0o C -0.007320 C
kf = 1.86 oC/m
ΔTf = i.kf x m
i = ΔTf/ kf x m
= 0.00732/1.82 x 0.0020
= 1.92 = 2
What is the [OH-] in the final solution prepared by mixing 20.0 mL of 0.50 M HCl with 30.0mL of 0.10 Ba(OH)2?
0.10 M
0.40 M
0.0050 M
0.0050 M
A.
0.10 M
Number of milliequivalents of HCl = 2 x 0.050 x 1 = 1
Number of milliequivalents of Ba(OH)2 = 2 x 30 x 0.10 = 6
[OH]- of final soluton
milliequivalent of Ba(OH)2 
Concentrated aqueous sulphuric acid is 98% H2SO4by mass and has a density of 1.80 g mL-1.Volume of acid required to make one litre of 0.1 M H2SO4 solution is:
11.10 mL
16.65 mL
22.20 mL
22.20 mL
D.
22.20 mL
25.3 g of sodium carbonate, Na2CO3 is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely molar concentration of sodium ion, Na+ and carbonate ion, CO32- are respectively (Molar mass of Na2CO3 = 106 g mol-1)
0.955 M and 1.910 M
1.910 M and 0.955 M
1.90 M and 1.910 M
1.90 M and 1.910 M
B.
1.910 M and 0.955 M
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