Which of the following occurs when an aqueous solution of sodium hydroxide is electrolysed using graphite electrodes?
- A. Sodium metal is produced at the anode
- B. Sodium amalgam is formed at the cathode
- C. Oxygen gas is produced at the anode
- D. The grahite anode dissolves
- E. The resulting solution becomes acidic
When naphthalene on heating changes from the solid state directly to the gaseous state it undergoes
- A. evaporation
- B. sublimation
- C. decomposition
- D. combustion
- E. ionisation
Calcium is usually extracted by the electrolysis of its
- A. trioxonitrate (V)
- B. tetraoxosulphate (IV)
- C. oxide
- D. hydride
- E. chloride
Polyatomicity is illustrated by molecules of
- A. sulphur
- B. carbon (IV) oxide
- C. noble gases
- D. liquefied oxygen
- E. liquefied nitrogen
The following will decolourize acidified potassium tetraoxomanganate (VII) solution except
- A. sulphur (lV) oxide
- B. but-3-ene
- C. pentane
- D. hydrogen sulphide
- E. propyne
Tetraoxosulphate (lV) acid is described as strong acid because it is highly
- A. corrosive
- B. concentrated
- C. reactive
- D. soluble in water
- E. ionized in water
The number of atoms in 1.2g of carbon – 12 isotope is
- A. 1.00 x 10 22
- B. 6.02 x 1022
- C. 1.20 x 10 23
- D. 1.00 x 1023
- E. 6.02 x 1024
The oxidation number of phosphorus in \(PO_4^{3-}\) is
- A. + 1
- B. +2
- C. +3
- D. +4
- E. +5
Which of the following would increase the rate of reaction of chips of a metal M as shown in the equation below? M(s) + 2HCI(aq) → MCI2(aq) + H2(g)
- A. Diluting the hydrochloric acid
- B. Adding some distilled water
- C. Decreasing the temperature
- D. Grinding the metal into powder
- E. Increasing the pressure
Which of the following is not a property of magnesium oxide?
- A. High melting point
- B. Dissolution in polar solvents
- C. Presence of ionic bonds
- D. Possession of crystal lattice
- E. Low binding energy
In any chemical reaction, the total mass of the products is always equal to that of the reactants. This is statement of the law of
- A. definite proportion
- B. conservation of matter
- C. multiple proportions
- D. reciprocal proportions
- E. constant composition
A measure of the degree of disorder in a chemical system is known as the
- A. enthalpy
- B. free energy
- C. activation energy
- D. entrophy
- E. equilibrium
Catalytic hydrogenation of alkenes produces compounds with the general formula
- A. CnH2n+1 OH
- B. CnH2n+1
- C. CnH2n+2
- D. CnH2n-2
- E. Cx(H2O)y
The number of replaceable hydrogen atoms in one acid indicates its
- A. basicity
- B. acidity
- C. alkalinity
- D. reactivity
- E. pH value
The components of universal indicator solution can best be separated by
- A. chromatography
- B. filtration
- C. evaporation
- D. crystallization
- E. fractional distillation
The alloy used for metal work and plumbing contains
- A. lead and tin
- B. iron and carbon
- C. copper and tin
- D. aluminium and copper
- E. lead and antimony
Zinc displaces copper from an aqueous solution of copper (ll) salt because
- A. copper is a transition element
- B. copper is a moderately reactive metal
- C. Zinc and copper have reducing prperties
- D. zinc is more reactive than copper
- E. zinc reacts with both acids and alkalis
When ammonium chloride is dissolved in water in a test tube, the tube feels colder showing that
- A. the solution is unsaturated
- B. sublimation has ocurred
- C. ammonia gas is evolved
- D. the process is endothermic
- E. condensation has occurred
The product of the reaction between ethanol and excess acidified K2Cr2O2 is
- A. ethanal
- B. ethylethanoate
- C. ethanoic acid
- D. ethyne
- E. ethanedioic acid
Which of the following is correct about the electrons in the 1s orbital? They
- A. have the same spin
- B. are easier to remove than those in the 2p orbital
- C. are closest to the nucleus
- D. have the same energy as those in the 2s orbital
- E. have different magnetic quantum numbers
Which of the following gases are diatomic except
- A. nitrogen
- B. helium
- C. hydrogen
- D. fluorine
- E. oxygen