SOLUTIONS QUIZ-7

Q1. Generally those gases are soluble in water to a greater extent which :

•  Are easily liquefied
•  Are ionized in water
•  React with water
•  All are correct

Solution
These are characteristics which reflect for high solubility of gases in water. It is therefore SO_2 and NH_3 having lower critical temperature or easily liquefied, HCl which ionises in water and CO_2 which reacts with water are more soluble

Q2.If the temperature increase from 0 ͦC to 50 ͦC at atmospheric pressure, which of the following processes is expected to take place more in case of liquids?

•  Freezing
•  Vaporization
•  Sublimation
•  None of these

Solution
An increase in temperature favours evaporation due to increase in average kinetic energy of molecules.

Q3.  Abnormal colligative properties are observed only when the dissolved non-volatile solute in a given dilute solution

•   Is a non-electrolyte
•  Offers an intense colour
•  Offers no colour
•  Associates of dissociates

Solution
As the colligative properties depend only upon the number of particles of solute, so if the non-volatile solute dissociate or associates in the solution, the value of colligative properties deviates, i.e., abnormal colligative properties are obtained

Q4. A solute is soluble in two immiscible liquids which are present in a mixture. The concentration of the solute in the upper layer will be :

•  Same as in the lower layer
•  Less than in the lower layer
•  More than in the lower layer
•  In fixed ratio with that in the lower layer

Solution
K=c_1/c_2

Q5.Distribution law is a special application of ….and vice-versa

•  Henry’s law
•  Raoult’s law
•  Dalton’s law
•  None of these

Solution
 Henry’s law involves two immiscible phases as gas-liquid; Distribution law involves two immiscible phases as liquid-liquid.

Q6. 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))

•  1000 g of solution
•  1 L of solution
• 1 L of solvent
•  1000 g of solvent

Solution
Molarity =(moles of solute )/(V of soution in litre ) ∴ Molar solution means 1 mole of solute is present in 1 L of solution.

Q7.In a 0.2 molal aqueous solution of a weak acid HX, the degree of ionisation is 0.3 Taking k_f for water as 1.85, the freezing point of the solution will be nearest to

•  +0.480℃
•  -0.260℃
•  -0.480℃
•  -0.360℃

Solution

Q8.Volume of 0.6 M NaOH required to neutralise 30 〖cm〗^3 of 0.4 M HCl is

•  40 〖cm〗^3
•  20 〖cm〗^3
•  45 〖cm〗^3
•  30 〖cm〗^3

Solution

Q9. The vapour pressure (VP) of a dilute solution of non-volatile solute is P and the VP of pure solvent is P_0, the lowering of the VP is :

•  P_0/P
•  P/P_0
•  -ve
•  +ve

Solution
Lowering is always positive.

Q10. In an osmotic pressure measurement experiment, a 5% solution of compound ‘X’ is found to be isotonic with a 2 % acetic acid solution . The gram molecular mass of ‘X’ is

•  60
•  150
•  300
• 24

Solution