Transition metals possess variable oxidation states because they have
- A. Electrons in the d orbitals
- B. Electron in the s orbitals
- C. A variable number of electrons in the p orbitals
- D. Partially filled p orbitals
Alloys are best prepared by
- A. Electroplating
- B. Arc-welding
- C. Reducing and mixture of their metallic oxide
- D. Cooling a molten mixture of the metals
Aluminium hydroxide is used in the dyeing industry as a
- A. Salt
- B. Dye
- C. Mordant
- D. Dispersant
Carbon is tetravalent because
- A. The electrons in both the 2s and 2p orbitals are equivalent
- B. The electrons in all the orbitals of carbon are equivalent
- C. The 2s and 2p atomic orbitals hybridize
- D. All the atomic orbitals of carbon hybridize
Sulphur (IV) oxide bleaches by
- A. Reduction
- B. Oxidation
- C. Hydration
- D. Adsorption
When steam is passed over red-hot carbon, the substances produced are
- A. Hydrogen and trioxocarbonate (IV) acid
- B. Hydrogen, oxygen and carbon (IV) oxide
- C. Hydrogen and carbon (II) oxide
- D. Hydrogen and carbon (IV) oxide
Which of the following gases can be collected by the method of downward delivery?
- A. Chlorine
- B. Oxygen
- C. Ammonia
- D. Hydrogen
The allotrope of carbon used in the decolourization of sugar is
- A. Graphite
- B. Soot
- C. Charcoal
- D. Lampblack
Which of the following shows little or no net reaction when the volume of the system is decreased?
- A. H2(g) + I2(g) ↔ 2HI(g)
- B. 2NO2(g) ↔ N2O4(g)
- C. PCl5(g) ↔ PCl3(g) + Cl2(g)
- D. 2O3(g) ↔ 3O2(g)
N\(_2\)O\(_4\),(g) ↔ 2NO\(_2\)(g)
In the endothermic reaction above, more product formation will be favoured by
- A. a constant volume
- B. an increase in pressure
- C. a decrease in pressure
- D. a decrease in volume
Which of the following hydrogen halides has the highest entropy value?
- A. HF
- B. HCl
- C. HBr
- D. HI
2CO(g) + O\(_2\)(g) → 2CO\(_2\)(g)
Given that ΔH[CO]is -110.4 kJmol-1 and ΔH[CO\(_2\)] is -393.0 kJmol-1, the energy change for the reaction above is
- A. -503.7 kJ
- B. -282.6 kJ
- C. +282.6 kJ
- D. +503.7 kJ
The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is
[Ag = 108, F = 96500 c mol-1]
- A. 108.0g
- B. 54.0g
- C. 27.0g
- D. 13.5gq
In the electrolysis of brine, the anode is
- A. platinum
- B. copper
- C. zinc
- D. carbon
Which of the following acts as both reducing and oxidized agent?
- A. H2
- B. SO2
- C. H2S
- D. CO2
ZnO(s) + CO(g) → Zn(s) + CO\(_2\)(g)
In the reaction above, Zinc has been
- A. decomposed
- B. displaced
- C. oxidized
- D. reduced
The oxidation state of chlorine in HClO\(_4\) is
- A. -5
- B. -1
- C. +1
- D. +7
What volume of 0.5 mol dm\(^{-3}\) H\(_2\)SO\(_4\) will exactly neutralize 20cm\(^3\) of 0.1 mol dm\(^{-3}\) NaOH solution?
- A. 2.0 cm3
- B. 5.0 cm3
- C. 6.8 cm3
- D. 8.3 cm3
Which of the following compound is a normal salt?
- A. NaHS
- B. NaHSO4
- C. NaHCO3
- D. Na2CO3
Calcium tetraoxosulphate (VI) dissolves in water only sparingly to form a
- A. solution
- B. suspension
- C. precipitate
- D. colloid
The solubility in moldm\(^{-3}\) of 20g of CuSO\(_4\) dissolved in 100g of water at 180\(^o\)C is
[Cu = 64, S = 32, O =16]
- A. 0.13
- B. 0.25
- C. 1.25
- D. 2.00