When concentrated sodium chloride solution is electrolysed using inert electrodes, the products are
- A. oxygen and hydrogen
- B. hydrogen and chlorine
- C. sodium and oxygen
- D. sodium and chlorine
If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the
- A. smaller mass
- B. lower electrical charge
- C. greater stability in solution
- D. stronger tendency to accept electrons
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
- A. 2.0 mole of Q 3+
- B. 2.5 mole of R2+
- C. 3.0 mole of T-
- D. 4.0 mole of Y-
Consider the following equation: Cr2O2-7(aq) + 14H+(aq) + 6e– → 2Cr3+(ag) + 7H2O(1). The oxidation number of chromium changes from
- A. -2 to + 3
- B. -2 to + 6
- C. +6 to +3
- D. +7 to + 6
A visible change is observed when a strip of iron is placed in an aqueous solution of
- A. FeSO4
- B. ZnSO4
- C. CuSO4
- D. MgSO4
Which of the following compounds will leave a metal residue when heated?
- A. Cu(NO3)2
- B. AgNO3
- C. K2CO3
- D. CaCO3
CuSO45H2O can be obtained from an aqueous solution of copper (ll) tetraoxosulphate (VI) by
- A. evaporation to dryness
- B. using chromatography
- C. precipitation
- D. crystallization
Equal amounts of marble chips are reacted separately with 100cm3 of hydrochloric acid of different concentrations. If all the marble chips reacted; which of the following remained the same in each case?
- A. Average rate of evoluton of gas
- B. Total mass of gas evolved during the reaction
- C. Time taken for the reaction to reach completion
- D. Initial reaction rates
What is the expression for the equilibrium constant (Kc) for the following reaction? N2(g) + O2(g) ⇌ 2NO(g)
- A. \(\frac{[NO^2]}{[N^2] + [O^2]}\)
- B. \(\frac{[2NO]^2}{[N_2][O_2]}\)
- C. \(\frac{[N_2] + [O_2]}{2[NO]^2}\)
- D. \(\frac{[NO]^2}{[N_2][O^2]}\)
What will happen if more heat is applied to the following system at equilibrium?
X\(_2\)(g) + 3Y\(_2\)(g) ⇌ 2XY\(_3\)(g); ∆H = xKJmol\(^{-1}\)
- A. the yield of XY 3 will decompose
- B. more of XY3 will decompose
- C. More of X2 will react
- D. the forward reaction will remain static
Which of the following salt solutions will have a pH greater than 7?
- A. NaCI(aq)
- B. Na2CO3(aq)
- C. Na2SO4(aq)
- D. NaHSO4(aq)
Calculate the mass of sodium hydroxide in 5.00 dm3 of a 0.125 mol dm-3 solution. [NaOH = 40 g mol-1]
- A. 0.0156 g
- B. 0.625 g
- C. 1.00 g
- D. 25.0 g
Which of the following substances increases in mass when heated in air?
- A. Sodium chloride
- B. lodine crystals
- C. Magnesium ribbon
- D. Copper (ll) oxide
A substance is said to be hygroscopic if it absorbs
- A. water from the atmosphere to form a solution
- B. heat from the surrounding
- C. carbon (IV) oxide from the atmosphere
- D. moisture from the atmosphere without dissolving
Which of following acids forms normal salts only?
- A. Tetraoxosulphate (VI) acid
- B. Trioxosulphate (IV) acid
- C. Acetic acid
- D. Tetraoxophosphate (V) acid
A major factor considered in selecting a suitable method for preparing a simple salt is its
- A. crystalline form
- B. melting point
- C. reactivity with dilute acids
- D. solubility in water
The gas given off when NH4 Cl is heated with an alkali is
- A. H2
- B. Cl2
- C. N2
- D. NH3
Determine the mass of sulphur (IV) oxide obtained when 91.0g of oxygen reacts completely with sulphur according to the following equation: S(s) + O\(_2\)(g) → SO\(_2\)(g) [S = 32; O = 16]
- A. 123g
- B. 139g
- C. 155g
- D. 182g
Calculate the mass of chlorine gas which occupies a volume of 1.12 dm\(^3\) a volume of 1.12 dm\(^3\) at s.t.p [Cl = 35.5, 1 mole og gas occupies 22.4 dm\(^3\) at s. t. p ]
- A. 1.80g
- B. 3.55g
- C. 7.10g
- D. 15.50g
What volume of hydrogen will be produced if 100cm3 of ammonia is completely decomposed at constant temperature and pressure? The equation for reaction is 2NH3(g) → N2(g) + 3H2(g)
- A. 50cm3
- B. 150cm3
- C. 200cm3
- D. 300cm3
Which of the following decreases when a given mass of gas is compressed to half its initial volume?
- A. Average intermolecular distance
- B. Frequency of collisions
- C. Number of molecules present
- D. Atomic radius of each particle