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4,306 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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4,306 questions

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Question 1781

jamb 1991

Addition of aqueous ammonia to a solution of Zn⁺⁺ gives a white precipitate which dissolves in an excess of ammonia because?

Azinc is amphoteric

Bzinc hydroxide is readily soluble

Czinc forms a complex which is readily soluble in excess ammonia

Dammonia solution is a strong base

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Question 1782

jamb 1991

Oxygen gas can be prepared by heating?

Aammonium trioxonitrate (V)

Bammonium trioxonitrate (III)

Cpotassium trioxonitrate (V)

Dmanganese (IV) oxide

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Question 1783

jamb 1991

Which of the following salts can be melted without decomposition?

ANa₂CO₃

BCaCO₃

CMgCO₃

DZnCO₃

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Question 1784

jamb 1991

Which of the following gases will rekindle a brightly glowing splint?

ANO₂

BNO

CN₂O

DCI₂

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Question 1785

jamb 1991

Which of the following equilibria is unaffected by a pressure change?

A2NaCI(s) ↔ 2Na _(I) + CI_2(g)

BH _2(g) + I_2(g) ↔ 2HI_(g)

C2O_3(g) ↔ 3O_2(g)

D2NO_2(g) ↔ N₂O_4(g)

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Question 1786

jamb 1991

NO(g) + CO(g) ↔ (1)/(2)N2(g) + CO2(g) ∆H = 89.3 kj.
What conditions would favour maximum conversion of nitrogen (II) oxide and carbon (II) oxide in the reaction above?

ALow temperature and high pressure

BHigh temperature and low pressure

CHigh temperature and high pressure

DLow temperature and low pressure

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Question 1787

jamb 1991

1.1 g of CaCI2 dissolved in 50 cm3 of water caused a rise in temperature of 3.4°C. The heat of reaction, ∆H for CaCI2 in kj per mole is?

(Ca = 40, CI = 35.5, specific heat of water is 4.18 jk-1)

A-71.1

B-4.18

C+71.1

D+111.0

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Question 1788

jamb 1991

Magnesium (IV) oxide is known to hasten the decomposition of hydrogen peroxide. Its main action is to?

Aincrease the surface area of the reactants

Bincrease the concntration of the reactants

Clower the activation energy for the reaction

Dlower the heat of reaction, ∆H, for the reaction

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Question 1789

jamb 1991

2H2S(g) + SO2(g) → 3S(s) + 2H2O(I). The above reaction is?

Aa redox reaction H₂S is the oxidant and SO₂ is the reductant

Ba redox reaction in which SO₂ is the oxidant and H₂S is the reductant

Cnot a redox reaction because there is no oxidant in reaction equation

Dnot a redox because there is no reductant in the reaction equation

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Question 1790

jamb 1991

MnO^-₄ + 8H⁺ + ne → Mn⁺⁺ + 4H₂O. Which is the value of n in the reaction above?

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Question 1791

jamb 1991

Which of the following equimolar solutions, Na₂CO₃ Na₂ SO
₄CI FeCI₃ CH₃COONa,
have pH greater than 7?

AFeCI ₃ and NH ₄CI

BNa₂CO₃, CH₃COONa and Na,Na₂SO₄

CNa₂CO₃ and CH₃COONa

DFeCI₃, CH₃COONa and NH₄CI

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Question 1792

jamb 1991

If a current of 1.5 A is passed for 4.00 hours through a molten tin salt and 13.3g of tin is deposited, what is the oxidation state of the metal in the salt?

(Sn = 118.7, F = 96500 C mol^-1)

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Question 1793

jamb 1991

What volume of CO\(_2\) at s.t.p would be obtained by reacting 10cm\(^3\) of 0.1M solution of anhydrous sodium trioxocarbonate (IV) with excess acid?

(G.M.V at s.t.p = 22.4 dm\(^3\))

A2.240 cm ³

B22.40 cm ³

C224.0 cm ³

D2240 cm ³

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Question 1794

jamb 1991

How many structural isomers can be written for the alkyl bromide, C₄H₉Br?

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Question 1795

jamb 1991

50 cm\(^3\) of sulphur (IV) oxide, 800cm\(^3\) of ammonia, 450 cm\(^3\) of hydrogen chloride, 1.0 cm\(^3\)of Carbon(IV) oxide will respectively saturate 1.0 cm\(^3\) of water at 15°C. Which of the following is suitable for demonstrating the fountain experiment?

ASulphur (IV) oxide and hydrogen chloride

BCarbon (IV) oxide and ammonia

CAmmonia and hydrogen chloride

DCarbon (IV) oxide and surphur (IV) oxide

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Question 1796

jamb 1991

A property of a colloidal dispersion which a solution does not have is?

Athe Tyndall effect

Bhomogeneity

Cosmotic pressure

Dsurface polarity

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Question 1797

jamb 1991

A sample of temporary hard water can be prepared in the laboratory by?

Adisolving calcium chloride in distilled water

Bsaturating lime water with carbon (IV) oxide

Csaturating distilled water with calcium hydroxide

Ddissolving sodium hydrogen trioxocarbonate (IV) in some distilled water

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Question 1798

jamb 1991

The solubility of copper (II) tetraoxosulphate (Iv) is 75g in 100g of water at 100°C and 25g in 100g of water at 30°C. What mass of the salt would crystallize, if 50g of copper (II) tetraoxosulphate (VI) solution saturated at 100°C were cooled to 30°C ?

A57.5

B42.2

C28.6

D14.3

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Question 1799

jamb 1991

Which of the following ions is a pollutant in drinking water even in trace amounts?

ACa²⁺

BHg²⁺

CMg²⁺

DFe²⁺

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Question 1800

jamb 1991

A quantity of air was passed through a weighed amount of alkaline pyrogallol. An increase in the weight of the pyrogallol would result from the absorption of?

Anitrogen

Bneon

Cargon

Doxygen

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