Chemistry Past Questions And Answers
The most stable allotropic form of sulphur at normal conditions is _______
- A) monoclinic sulphur
- B) rhombic sulphur
- C) amorphous sulphur
- D) plastic sulphur
Tetraoxosulphate (lV) acid is described as strong acid because it is highly
- A. corrosive
- B. concentrated
- C. reactive
- D. ionized in water
Potassium trioxochlorate (V) undergoes thermal decomposition according to the fotpowing equation: 2KCIO\(_3\) \(\to\) 2KCI + 3O\(_2\)
(a) What substance could be used in the laboratory to in ease the rate of the reaction
(ii) absorb the oxygen produced
(b) Give the reason why an aqueous solution of silver trioxonitrate (V) gives a white precipitate with KCI but not with KClO\(_3\).
View Discussion (0)WAEC 1994 THEORYThe sulphide that is commonly used in coating electric fluorescent tubes is?
- A. iron(ii)Sulphide
- B. tin(ii)sulphide
- C. Zinc Sulphide
- D. lead(iv) Sulphide
Consider the reaction represented by the equation below: H2(g) + 12(s) ------> 2HI(g) ΔH negative. Which of the following takes place when the temperature of the reaction vessel is decreased?
- A. the gases condense
- B. the yield of hydrogen increases
- C. the concentration of the reactants remain constant
- D. the yield of hydrogen iodide increases
The arrangement of particles in crystal lattices can be studied using
- A) X-rays
- B) β-rays
- C) α-rays
- D) γ-rays
(a)(i) Define ionic bond.
(ii) What type of bond (s) exist (s) in: I. magnesium oxide; II. ammonium ion?
(b) Determine the oxidation number of sulphur in Na\(_2\)S\(_2\)O\(_2\).
(c) State Faraday's first law.
(d) Give one example each of: (i) acid salt; (ii) base salt.
(e) Name the type of energy change that occurs in each of the following processes
(i) I\(_{2(s)}\) \(\to\) I\(_{2(g)}\)
(ii) Cl\(_{(g)}\) + e\(^{-}\) \(\to\) Cl\(^{-_(g)}\)
(f) State the effect of each of the following aqueous solutions on litmus paper: (i) Na\(_2\)SO\(_{4(aq)}\) (ii) AlCl\(_{3(aq)}\)
(g) Define the term efflorescence.
(h) Give two uses of activated charcoal.
(i) State one use of each of the following processes in the chemical industry: (i) hydrogenation of vegetable oil; (ii) cracking; (iii) esterification.
(j) Calculate the amount of silver deposited in moles when 10920 coulombs of electricity is passed through a solution of a silver salt. [ Faraday constant-- 96500 C mol\(^{-1}\)]
View Discussion (0)WAEC 2014 THEORYThe oxidation state of chlorine in NaClO3 is?
- A. +1
- B. +3
- C. +5
- D. +6
Elements in the same period in the periodic table have the same
- A) number of shells
- B) atomic number
- C) chemical properties
- D) physical properties
Atomicity of ozone is
- A) 1
- B) 2
- C) 3
- D) 4