ABU Chemistry 2015/2016 Past Questions

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In the reaction between sodium hydroxide and sulphuric acid solutions. What volume of 0.5molar sodium hydroxide would exactly neutralize 10cm³ of sulphuric acid

A.5CM³
B.10CM³
C.20CM³
D.25CM³
E.50CM³

A small quantity of solid ammonium chloride(NH₄Cl) was heated gently in a test tube. The solid gradually disappear to produce a mixture of two gases later a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone.

A.distillation
B.sublimation
C.precipitation
D.evaporation
E.decomposition

Element P,Q,R,S have 6,11 & 17 electrons respectively. Therefore

A.P will form an electrovalent bond with R
B.Q will form a covalent bond with S
C.R will form an electrovalent bond with S
D.Q will form an electrovalent bond with S
E.Q will form a covalent bond with R

An element X forms the following compounds with chlorine: NCl₄,XCL₃,XCl₂ this illustrates the

A.law of multiple proportions
B.law of chemical proportions
C.law of simple proportions
D.law of conservation of mass
E.law of definite proportion

The oxidation state of chlorine in potassium chloride is

A.11
B.12
C.13
D.15
E.17

When carbondioxide is bubbled into limewater, a white precipitate is formed this is

A.Calcium carbonate is formed which on reaction dissolves
B.calcium hydrogen carbonate is precipitated and then dissolves
C.calcium carbonate is formed which on reaction with solution has occurred with the deposition of calcium hydroxide
D.concentration of solution has occurred with the deposition of calcium hydroxide
E.The solution has become saturated and solid carbon dioxide has been deposited

The following reactions are stages in important industrial processes:
(I) N₂ + O₂ ←2NH_3(g). ΔH is negative
(II) 2SO_2(g) + O_8(g) ← @SO_3(g) ΔH is negative
(III) N_2(g) + O_2(g) ← 2NO_(g) ΔH is positive. Which of the above forward reactions is favoured by (i) a decrease in the concentration of the pressure and (ii) an increase in temperature?

A.i
B.ii
C.iii
D.i&ii
E.i&iii

Methanoic acid mixes with water in all proportions and has about the same boiling point asd water. Which of the following methods would you adopt to obtain pure water from a mixture of sand, water and methanoic acid

A.Fractional distillation
B.filtration followed by aestivation
C.neutralities with sodium hydroxide followed by distillation
D.neutralities with sodium hydroxide followed by filtration
E.etherification with ethanol followed by distillation

Which of the following statements applies during the electrolysis of sodium hydroxide solution using platinum electrodes?

A.Anions are discharge at the cathode
B.hydrogen ions are discharged at the anode
C.the concentration sodium hydroxide decreases at both the anode
D.the concentration sodium hydroxide increases at the cathode only
E.The concentration of sodium hydroxide at the anode only

Which of the following statement is true? when potassium atom forms its ion

A.it gains one electron and becomes neutral
B.its atomic number decreases
C.it acheives electronic configuration of argon
D.it loses proton
E.it loses one neutron