SOLUTIONS QUIZ-6

Q1. Vapour pressure of chloroform (CHCl_3) and dichloromethane (CH_2 Cl_2) at 25°C are 200 mm Hg and 41.5 mm Hg respectively. Vapour pressure of the solution obtained by mixing 25.5 g of CHCl_3 and 40 g of CH_2 Cl_2 at the same temperature will be : (Molecular mass of CHCl_3=119.5 u and molecular mass of CH_2 Cl_2=85 u)

•  173.9 mm Hg
•  615.0 mm Hg
•  347.9 mm Hg
•  90.952 mm Hg

Solution

Q2.A solution is prepared by dissolving 24.5 g of sodium hydroxide in distilled water to give 1L solution. The molarity of NaOH in the solution is (Given, that molar mass of NaOH = 40.0 g 〖mol〗^(-1))

•  0.2450 M
•  0.6125 M
•  0.9800 M
•  1.6326 M

Solution

Q3.  The molal elevation constant for water is 0.52 K molality^(-1). The elevation caused in the boiling point of water by dissolving 0.25 mole of a non-volatile solute in 250 g of water will be :

•   52 ͦC
•  5.2 ͦC
•  0.052 ͦC
•  0.52 ͦC

Solution
∆T_f=(1000 ×0.52×0.25)/250=0.52 ͦC

Q4. The phenomenon in which cells are shrinked down if placed in hypertonic solution is called :

•  None of these
•  Endosmosis
•  Haemolysis
•  Plasmolysis

Solution
The exosmosis occurs from cell to solution (hypertonic or high osmotic pressure or high concentration)..

Q5.Two solutions of glucose have osmotic pressure 1.0 and 3.5 atm. If 1 L of first solution is mixed with V L of second solution, the osmotic pressure of the resultant solution becomes 2.5 atm. Volume of second solution isTwo solutions of glucose have osmotic pressure 1.0 and 3.5 atm. If 1 L of first solution is mixed with V L of second solution, the osmotic pressure of the resultant solution becomes 2.5 atm. Volume of second solution is

•  1.5 L
•  2.5 L
•  1.0 L
•  3.5 L

Solution

Q6. The difference between the boiling point and freezing point of an aqueous solution containing sucrose (mol wt. = 342 gmol^(-1)) in 100 g of water is 105.0^∘ C. If K_f and K_b of water are 1.86 and 0.51 K kg mol^(-1) respectively, the weight of sucrose in the solution is about

•  34.2 g
•  72 g
• 7.2 g
•  342 g

Solution

Q7. At temperature 327℃ and concentration C osmotic pressure of a solution is p, the same solutions at concentration C/2 and a temperature 427℃ shows osmotic pressure 2 atm, value of p will be

•  12/7
•  5/6
•  24/7
•  6/5

Solution

Q8.A non-ideal solution was prepared by mixing 30 mL chloroform and 50 mL acetone. The volume of mixture will be

•  >80 mL
•  =80 ML
•  =80 mL
•  ≥80 mL

Solution

Q9.The solubility of a gas in liquid at a temperature is directly proportional to its :

•  Density
•  Melting point
•  Boiling point
•  Pressure

Solution
Amount of gas dissolved per unit volume ∝pressure of gas; this is Henry’s law.

Q10. Binary liquid mixtures which exhibit positive deviations from Raoult’s law boil at…. temperature than the expected b. p.:

•  lower
•  Higher
•  Same
• Cannot be said

Solution
Liquid mixtures showing positive deviations from Raoult’s law posses lower b. p..