If \(100^3\) of a saturated solution of sodium tetraoxosulphate (VI) at 30° C contains 10.5 g of the salt, what would be its solubility at this temperature? [\(Na_2SO_4\) = 142]

• A. 2.15 mol dm^-3
• B. 0.74 mol dm^-3
• C. 0.60 mol dm^-3
• D. 0.57 mol dm^-3

A solution which on treatment with hydrochloric acid produces a colourless, odourless gas which turns lime water milky is most likely to be a

• A. trioxonitrate (V)
• B. chloride
• C. trioxocarbonate (IV)
• D. hydroxide

If the difference in electronegativity of elements P and Q is 3.0. The bond that will be formed between them is

• A) metallic
• B) covalent
• C) co-ordinate
• D) ionic

The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is

• A. hydrogen
• B. oxygen
• C. carbon (IV) oxide
• D. sulphur (VI) oxide

(a) (i) State three characteristic properties of transition metals.

(ii) What is the oxidation state of manganese In each of the following species? (1) MnCl\(_2\) (II) MnO\(_2\) (III) MnO\(_4^{-}\)

(iii) Explain why manganese conducts electricity in the solid state but manganese chloride conducts only when molten or in solution.

(b)(i) The collision theory suggests that for two particles to react, they must collide. What two factors determine whether or not the collision would lead to formation of products?

(ii) Use an energy profile diagram to illustrate what is meant by the enthalpy change (\(\Delta\)H) and the activation energy (E\(_A\)) of a reaction.

(c) When few drops of aqueous KSCN are added to a solution of iron (III) salt the following equilibrium is set up:

Fe\(^{3}_{(aq)}\) + 3SCN\(^{-}_{(aq)}\) \(\rightleftharpoons\) Fe(SCN)\(_{3(aq)}\)

yellow colourless deep red

The equilibrium mixture has a pale red colour.

(i) Explain what would happen if more KSCN\(_{(aq)}\) were added to the equilibrium mixture.

(ii) Which of the ions in the equilibrium mixture forms an insoluble hydroxide with NaOH\(_{(aq)}\)? Write an equation for the reaction

(iii) State two changes observed on adding NaOH\(_{(aq)}\) to the equilibrium mixture.

What volume of oxygen is produced from the decomposition of 2 mole of KCIO₃ at s.t.p? [Molar volume of a gas at s.t.p = 22.4 dm³]

• A. 22.4 dm3
• B. 33.6 dm3
• C. 44.8 dm3
• D. 67.2 dm3

A side effect of soft water is that

• A. it gives offensive taste
• B. excess calcium is precipitated
• C. it attcaks lead contained in pipes
• D. it encourages the growth of bacteria

Chromatography is used to separate components of mixtures which differ in their rates of?

• A. diffusion
• B. migration
• C. reaction
• D. sedimentaion

State which of the following can exhibit geometric isomerism:

Give reason for your answer

Group 1 A metals are not found free in nature because they?

• A. are of low melting and boiling points
• B. have weak metallic bonding
• C. conduct electricity and heat
• D. are very reactive