Solutions

Question 1

brass

Answer 1

mixture of copper and zinc

Question 2

german silver

Answer 2

mixture of copper, zinc and nickel

Question 3

bronze

Answer 3

mixture of copper and tin

Question 4

sodium fluoride is used in

Answer 4

rat poison

Question 5

what prevents tooth decay?

Answer 5

1 part per million (ppm) of fluoride ions in water prevents tooth decay

Question 6

1.5 ppm causes the tooth
to become

Answer 6

mottled/spotted

Question 7

high concentration of fluoride ions can be

Answer 7

poisonous

Question 8

Concentration described by mass percentage is commonly used in

Answer 8

industrial chemical applications.

Question 9

commercial bleaching solution contains

Answer 9

3.62 mass percentage of sodium hypochlorite in water

Question 10

Mass by volume % (w/V) is commonly used in

Answer 10

medicine and pharmacy

Question 11

Mole fraction unit is very useful in

Answer 11

relating some physical properties of solutions

Question 12

Applications of Henry’s law

Answer 12

-CO₂ in soft drinks
-Bends due to formation of bubbles which block capillaries.
-high altitudes, the partial pressure of oxygen is lesser hence the solubility

Question 13

The tanks used by scuba divers are filled with

Answer 13

11.7% helium, 56.2% nitrogen and 32.1% oxygen

Question 14

the decrease in the vapour pressure of solvent depends on the

Answer 14

non-volatile solute present in the solution, irrespective of its nature

Question 15

Examples of an Ideal solution

Answer 15

-n-hexane and n-heptane
-bromoethane and chloroethane
-benzene and toluene

Question 16

examples of positive deviation

Answer 16

-Mixtures of ethanol and acetone
-carbon disulphide and acetone
-ethanol and water mixture

Question 17

example of negative deviation

Answer 17

-mixture of phenol and aniline
-mixture of chloroform and acetone
-mixture of Nitric acid and water

Question 18

how is ethanol-water mixture is obtained?

Answer 18

by fermentation of sugars

Question 19

azeotrope composition of ethanol-water

Answer 19

approx. 95% by volume of ethanol

Question 20

the azeotropic composition of nitric acid and water

Answer 20

68% nitric acid and 32% water by mass with a b.p. of 393.5 K

Question 21

brine

Answer 21

salt water

Question 22

the osmotic pressure associated
with the fluid inside the blood cell is equivalent to that of

Answer 22

0.9% (mass/volume) sodium chloride solution, called normal saline
solution

Question 23

swelling and puffiness in the body is called

Answer 23

edema

Question 24

Reverse osmosis is used in

Answer 24

desalination of sea
water

Question 25

molecules of ethanoic acid (acetic acid) dimerise in

Answer 25

benzene due to hydrogen bonding