Charcoal is used in the decolourization of sugar because of its
absorption property.
amorphous property.
oxidizing property.
adsorption property.
Correct answer is D
Wood charcoal is used to decolourise sugar because it has a highly porous structure, providing a large surface area for adsorption. Therefore, it adsorbs coloured material from sugar.
40
48
61
101
Correct answer is A
Molar mass of X(HCO3)2 = X+(1+12+(16*3))2=162
=X + (13+48)2=162
X + 122=162
X=162-122
X=40
Which of the following processes occur during fractional distillation of petroleum?
Condensation and diffusion
Diffusion and evaporation
Diffusion and sublimation
Evaporation and condensation
Correct answer is D
Fractional distillation is a series of processes of evaporation and condensation at a number of points in a vertical column.
Which of the following oxides is amphoteric?
Carbon(II) oxide
Nitrogen(IV) oxide
Lead(II) oxide
Calcium oxide
Correct answer is C
Aluminium oxide is an amphoteric oxide. With sodium hydroxide solution, it produces water and sodium aluminate (NaAlO2). The other common examples of amphoteric oxides include SnO, ZnO, and PbO. Al2O3 is an amphoteric oxide.
| Substitute | Meltig point / ºC | Boiling point / ºC |
| P | - 78 | -25 |
| Q | - 8 | 40 |
| R | - 6 | 150 |
| S | 44 | 280 |
Which of the substances is a liquid at room temperature and rapidly evaporates on exposure to air?
P
Q
R
S
Correct answer is B
Q has slightly lower boiling point which when expose to air may evaporate rapidly.