The oxidation number of iodine in the iodate ion (IO –3) is
- A. -5
- B. -1
- C. +1
- D. +5
Electrolysis is applied in the following processes except
- A. electroplating
- B. extraction of aluminium
- C. extraction of iron
- D. purification of copper
Consider the reaction represented by the equation: 2SO\(_{2(g)}\) + O\(_{2(g)}\) ⇌ 2SO\(_{3(g)}\); ∆H = – 197 kJmol\(^{-1}\). Which of the following conditions will not increase the yield of sulphur (VI) oxide?
- A. Increase in temperature
- B. Decrease in temperature
- C. Increase in pressure
- D. Addition of O2 into the mixture
Which of the following compounds absorbs moisture from the atmosphere and dissolves in it?
- A. FeCI3
- B. MgSO4.7H2O
- C. Na2SO 4
- D. KCI
When aqueous ammonia is added to one of the following solutions,a white precipitate which dissolved in excess ammonia is formed Identify the solution.
- A. ZnCl2(aq)
- B. Pb(NO3)2(aq)
- C. CuSO4(aq)
- D. FeSO4(aq)
The indicator used in neutralizing CH3COOH and NaOH solution has pH range of
- A. 3-5
- B. 7-8
- C. 8-103
- D. 10-12
Which of the following aqueous methods cannot be used to distinguish between a strong acid and a a weak acid?
- A. Conductivity measurement
- B. Measurement of pH
- C. Measurement of heat of neutralization
- D. Action on starch iodide paper
Which of the following processes is an endothermic reaction?
- A. Dissolving NH4CI crystals in water
- B. Addition of concentrated H2SO4
- C. Dissolving NaOH pellets in water
- D. Passing SO3 gas into water
Considered the reaction: H+(aq) + OH – (aq) → H2O
(l). The energy change taking place in the reaction above is enthalpy of
- A. formation
- B. hydration
- C. neutralization
- D. solution
Consider the reaction represented by the equation. 2NaHCO3(s) \(\rightarrow\) 2Na2CO 3(S) + CO 2(g) + H2O(g) what volume of carbon (IV)oxide at s.t.p is evolved when 0. 5 moles of NaHCO3 is heated? [Molar volume = 22.4 dm3 at s.t. p]
- A. 1.12dm3
- B. 2.24dm3
- C. 5.6dm3
- D. 56.0dm3
If 20 cm3 of distilled water is added to 80cm 3 of 0. 50 mol dm-3 hydrochloric acid, the new concentration of the acid will be
- A. 0.10mol dm-3
- B. 0.20mol dm-3
- C. 0.40mol dm-3
- D. 2.00mol dm-3
If 1 mole of sodium contains 6 x 1023 atoms, how many atoms are contained in 0.6 g of sodium? [Na = 23]
- A. 1.56 x 1023
- B. 1.56 x 1022
- C. 3.6 x 1023
- D. 3.6 x 1022
An atom 23892X decays by alpha particle emission to give an atom Y. The atomic number and mass number of Y are
- A. 90 and 234 respectively
- B. 91 and 238 respectively
- C. 92 and 236 respectively
- D. 93 and 238 respectively
An element X has isotopic masses of 6 and 7. if the relative abundance is 1 to 12.5 respectively, what is the relative atomic mass of X?
- A. 6.0
- B. 6.1
- C. 6.9
- D. 7.0