solutions

Question 1

solutions

Answer 1

homogenous mixture of two or more components

Question 2

composition of a solution can be expressed by _______

Answer 2

expressing its concentrations

Question 3

qualitative ways of expressing a solutions concentration

Answer 3

dilute
concentrated

Question 4

quantitative ways of expressing a solutions concentration

Answer 4

mole fraction, mass%, molarity, molality.

Question 5

conc by ___is used in industrial chemical applications

Answer 5

mass%

Question 6

solubility

Answer 6

max amount that can be dissolved in a specified amount of solvent at a specified temperature.

Question 7

factors affecting solubility

Answer 7

• nature of solvent
• nature of solute
• temperature
• pressure

Question 8

dissolution

Answer 8

when a solid solute is added to the solvent some solute dissolves and its conc increases in a solution.

Question 9

crystallization

Answer 9

some solute particles collide withe the solid solute particles and get separated out of the solutions.

Question 10

how eqbm is attained b/w dissolution and crystallization

Answer 10

• when dissolution and crystallization occur at a same rate, the no. of solute particles going out of the solution will be equal to the no of particles separating out and a state of dynamic eqbm is reached.

Question 11

why pressure does not have any significant effect on solubility.

Answer 11

• bec. solids and liquids are highly incompressible and practically remain unaffected by changes in pressure.

Question 12

Kh and solubility

Answer 12

inverse

Question 13

temp and solubility

Answer 13

inverse

Question 14

Kh and solubility

Answer 14

direct

Question 15

___ was teh 1st to give teh qualitative relation b/w pressure and solubility of a gas in a solvent which is known as Henry’s law.

Answer 15

Henry

Question 16

Henry’s law

Answer 16

the partial pressure of the gas in vapour phase is proportional to the mole fraction of the gas in the solution.
p=Kh X

Question 17

To increase the solubility of CO2 in soft drinks

Answer 17

The bottle is sealed under high pressure

Question 18

What is done to avoid bends in scuba divers?

Answer 18

• Scuba divers must cope with high concentrations of dissolved gases while breathing air at high pressure underwater. Increased pressure increases the solubility of atmospheric gases in blood. When the divers come towards surface, the pressure gradually decreases. This releases the dissolved gases and leads to the formation of bubbles of nitrogen in the blood. This blocks capillaries and creates a medical condition known as bends, which are painful and dangerous to life.
• To avoid bends, as well as, the toxic effects of high concentrations of nitrogen in the blood, the tanks used by scuba divers are filled with air diluted with helium (11.7% helium, 56.2% nitrogen and 32.1% oxygen).

Question 19

Who are affected by anoxia?

Answer 19

At high altitudes the partial pressure of oxygen is less than that at the ground level. This leads to low concentrations of oxygen in the blood and tissues of people living at high altitudes or climbers. Low blood oxygen causes climbers to become weak and unable to think clearly, symptoms of a condition known as anoxia.

Question 20

How is dissolution similar to crystallization?

Answer 20

Solubility of gases in liquids decreases with rise in temperature. When dissolved, the gas molecules are present in liquid phase and the process of dissolution can be considered similar to condensation and heat is evolved in this process.

Question 21

Raoult’s law

Answer 21

Raoults law states that for any solution the partial pressure of each volatile component in the solution is directly proportional to its mole fraction.

Question 22

Dalton’s law of partialpressures

Answer 22

The total pressure over the solution will be the sum of the partial pressure of the components of the solution.

Question 23

Raoult’s law as a special case of Henry’s law.

Answer 23

According to Raoult’s law, the vapour pressure of a volatile component
inagivensolutionisgivenbyp =x p0.Inthesolutionofagasina iii
liquid, one of the components is so volatile that it exists as a gas and we have already seen that its solubility is given by Henry’s law which states that
p = KH x.
If we compare the equations for Raoult’s law and Henry’s law, it
can be seen that the partial pressure of the volatile component or gas
is directly proportional to its mole fraction in solution. Only the
proportionality constant K differs from p 0. Thus, Raoult’s law becomes H1
a special case of Henry’s law in which K becomes equal to p 0.

Question 24

+ve déviation solution

Answer 24

Ethanol and acetone
Cs2 and acetone

Question 25

-ve deviation

Answer 25

Phenol and aniline
Chloroform and acetone

Question 26

Colligative property

Answer 26

The properties which depend on the number of solute particles irrespective of their nature relative to the total number of particles present in the solution.such properties are called colligative properties.

Question 27

Rlvp =

Answer 27

Mole fraction of solute

Question 28

Spm

Answer 28

Membranes in which small solvent molecules like water can pass through these holes but the passage of bigger molecules like solute is hindered.

Question 29

Osmosis

Answer 29

The process in which solvent molecules flow from the solvent to the solution through a spm till eqbm is attained is called osmosis.

Question 30

Osmotic pressure

Answer 30

The pressure that stops the flow of solvent is called osmotic pressure of the solution.

Question 31

Edema

Answer 31

People taking a lot of salty food experience water retention in tissue celles and intercellular spaces because of osmosis. The resulting puffiness or swelling is called edema.

Question 32

Advantage of osmotic pressure over other colligative property

Answer 32

• pressure measurement is around room temperature.
• molarity of the solution is used instead of molality.
• the technique of osmotic pressure for determination of molar mass of solutes is particularly useful for bio molecules as they are generally not stable at higher temperatures and polymers have poor solubility.
• the magnitude is very large for very dilute solutions.

Question 33

Isotonic solution

Answer 33

Two solutions having the same osmotic pressure at a given temperature.

Question 34

Isotonic, hypertonic and hypotonic wrt nacl solution

Answer 34

Isotonic= 0.9%
Hypertonic= less than 0.9%
Hypotonic= greater than 0.9%

Question 35

Reverse osmosis

Answer 35

The direction of osmosis can be reversed if a pressure larger than the osmotic pressure is applied to the solution side. That is, now the pure solvent flows out of the solution through the semi permeable membrane. This phenomenon is called reverse osmosis and is of great practical utility.

Question 36

Reverse osmosis in desalination of sea water

Answer 36

• diagram in tb
  When pressure more than osmotic pressure is applied, pure water is squeezed out of the sea water through the membrane. A variety of polymer membranes are available for this purpose.

Question 37

Use of cellulose acetate for reverse osmosis

Answer 37

The pressure required for the reverse osmosis is quite high. A workable porous membrane is a film of cellulose acetate placed over a suitable support. Cellulose acetate is permeable to water but impermeable to impurities and ions present in sea water. These days many countries use desalination plants to meet their potable water requirements.

Question 38

when there is dissociation of solute into ions,

Answer 38

when there is dissociation of solute into ions, the experimentally determined molar mass is always lower than the true value.

Question 39

Dimerization in ethanoic acid

Answer 39

Molecules of ethanoic acid (acetic acid) dimerise in benzene due to hydrogen bonding. This normally happens in solvents of low dielectric constant. In this case the number of particles is reduced due to dimerisation.

Question 40

Determining association and dissociation wrt i

Answer 40

In case of association, value of i is less than unity while for dissociation it is greater than unity.