Correct Answer: D. Control panel

Explanation

Control panel. It is a component of microsoft Windows that provides the ability to view and change system settings. It consists of a set of applets that include adding or removing hardware and software, controlling user accounts, changing accessibility options and accessing networking settings.

Correct Answer: A. some towns contain features of rural living

Correct Answer: C. 5.0m/s

Correct Answer: C. y=x²-x-2

Correct Answer: A. commercial

Correct Answer: A. appearance and origin

Correct Answer: B. Salary arrears paid in the current year

Correct Answer: C. local action

Explanation

If the zinc used in the simple cell is of the impure commercial variety bubbles of hydrogen will be seen coming off the zinc. This is called local action.

Correct Answer: A. seize

Explanation

(a)(i)

(ii) Two uses of each of the following compounds:

(1) Sodium Chloride - food seasoning, food preservative, glazing pottery/earthen ware. soap production, crude oil refilling, water softener, production of chlorine/hydrogen/ sodium metal, NaOH/NaClO\(_3\)/NaOCl/Na\(_2\)CO\(_3\) lowering melting point of ice preparation of freezing mixture. Used in tannery industry/tanning.

(2) Uses of sodium trioxocarbonate (IV) - Manufacture of glass/borax in detergents/ soaps, manufacture of paper softening hardwater, manufacture of NaOH treating (concentrated) acid splash, standardization of acids/analytical reagent.

(b)(i) Balanced equations for the reactions involved in the extraction of iron in the blast furnace.

C\(_{(g)}\) + O\(_{2(g)}\) ----> CO\(_{2(g)}\)

CO\(_{2(g)}\) + C\(_{(g)}\) --> 2CO\(_{(g)}\)

Fe\(_{2}\)O\(_{3}\) + 3CO\(_{(g)}\) \(\to\) 2Fe + 3CO\(_{2(g)}\)

CaO + SiO\(_{2}\) -> CaSiO\(_{3}\)

CaCO\(_{3}\) -> CaO + CO\(_{2}\)

(ii) Faraday's first law of electrolysis states that the mass of an element discharged at the electrode is directly proportional to the quantity of electricity passed through the electrolyte.

(iii) Two applications of electrolysis are: Electroplating of metals, Extraction of metals, Purification of metals, Preparation of compounds/elements, Production of gases H\(_{2}\), O\(_{2}\), Cl\(_{2}\) (any 2)

(c) Sugar crystals + concentrated H\(_{2}\)SO\(_{4}\) in a beaker. Observations are as follows:

(1) Concentrated acid dehydrates the sugar.

(2) A mass of carbon/black soot/ sugar charcoal is formed.

(3) Reaction is exothermic (heat evolved or released).

(d) Equations for the reaction of Zinc powder with dilute tetraoxosulphate (VI) acid:

(i) Zn\(_{(g)}\) + H\(_{2}\)SO\(_{4(aq)}\) -> ZnSO\(_{4(aq)}\) + H\(_{2(g)}\)

(ii) Reaction with dilute concentrated H\(_2\)SO\(_4\)

(iii) Zn\(_{(g)}\) + 2H\(_2\)SO\(_{4(aq)}\) -> ZnSO\(_{4(aq)}\) + SO\(_{2(g)}\) + 2H\(_2\)O\(_{(l)}\)

(e) Property of concentrated tetraoxosulphate (VI) acid shown in (d)(1) is oxidizing property.