Why will it always be more difficult to extract potassium ions from sea water than to extract magnesium ions? This is because

• A) most potassium compounds are less soluble in water
• B) most potassium compounds are quite soluble in water
• C) presence of other alkali metal ions has great influence on it
• D) magnesium ion is an alkaline earth metal ion

Which of the following metals is passive to concentrated trioxonitrate (V) acid?

• A. Iron
• B. Tin
• C. Copper
• D. Zinc

When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;

• A) nitrogen and carbondioxide
• B) the rare gases
• C) nitrogen and oxygen
• D) nitrogen and the rare gases

(a)(i) State two physical properties of hydrogen sulphide

(ii) Name the laboratory equipment used for intermittent production of hydrogen sulphide

(b) What property of hydrogen sulphide is illustrated in the reaction represented by the following equation?

H\(_2\)S\(_{(g)}\) + 2NaOH\(_{(aq)}\) \(\to\) Na\(_2\)S\(_{(aq)}\) + H\(_2\)O\(_{(l)}\)

Which of the following properties increases down the group in the Periodic Table?

• A) atomic radius
• B) electronegativity
• C) electron affinity
• D) ionization energy

Which of the following is not correct of the reaction represented by the equation below? 2C(s) + O₂(g) → 2CO(g); ΔH = - xKJ

• A. there is an increase in entropy ;
• B. There is anincrease in gaseous volume
• C. Carbon (lV) oxide is produced
• D. The oxidation number of carbon increases from 0 to +2

Which of the following is normally used for drying ammonia gas?

• A. Concentrated tetraoxonitrate (Vl) acid
• B. Calcium oxide
• C. anhydrous calcium chloride
• D. phosphorus (V) oxide

The basic property of salts used as drying agents is by?

• A. efforescence
• B. high melting point
• C. hygroscopy
• D. low solubility

The oxidation state of oxygen in tetraoxosulphate (VI) acid is

• A. -4
• B. -2
• C. +4
• D. -8

What quantity of Silver deposed when 985OOC of electricity is passed through a solution containing silver ons? (Ag = 108 F = 985000)

• A. 1.08g
• B.5.40g
• C. 108g
• D. 10.8g