JAMB UTME - Chemistry - 1979

Methanoic acid mixes with water in all proportions and has about the same boiling point as water which of the following methods would you adopt to obtain pure water from a mixture of stand, water and methanoic acid?

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The solution of a sample in a tube will be identified as a chloride if it gives

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The solution of a sample in a tube will be identified as a chloride if it gives a white precipitate when acidified with dilute HNO3 and then AgNO3 solution is added. This is because the test is a confirmatory test for chloride ions, and the white precipitate formed is silver chloride (AgCl). Chloride ions react with silver nitrate (AgNO3) to form a white precipitate of AgCl, which is insoluble in water and dilute nitric acid.

A piece of metal (M) is dissolved in nitric acid and the resulting solution is treated with a small quantity of sodium hydroxide to produce a white precipitate (B) which redissolves on the addition of excess alkali. The precipitate (B)when ignited in a crucible produces the oxide of the metal(m). The METAL M is

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In the redox reaction 2Fe²⁺ + CI₂ → 2Fe ^{3 +} + 2Cl

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Consider the following exothermic reaction 2SO₂(g) + O₂(g) = 2SO₃ (g) . If the temperature of the reaction is reduced from 800_oC to 500_oC, and no other change takes place, then

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The reaction 3C(s) + 2Fe₂O₃(s) = 4Fe(s) + 3CO₂(g): \(\Delta\)H =46.0 kJ is

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the vapour density of a gas may be defined as

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Helium atoms are chemically unreactive because

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One of the following techniques can be used to show that chlorophyll pigment is a mixture of chemical compounds and not a single coloured compound

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When ammonium, potassium and calcium carbonates are each separately heated

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When excess ethanol is heated to 145 ^oC in the presence of concentrated sulphuric acid, the product is

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Which one of these compounds will NOT give an oxygen gas on heating?

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Weighed salts Y and Z were left exposed in the laboratory overnight. In the morning Y had gained weight, and Z had become liquid. What conclusion could be drawn about the nature of the two salts?

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In the extraction of aluminum from purified bauxite by electrolysis, cryolite is used because

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In which of the following reactions is sulphur dioxide acting as an oxidizing agent?

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On heating anhydrous iron (ll) sulphate, in addition to producing iron (iii) oxide, which of the following is produced?

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Which of the following statements applies during the electroysis of sodium hydroxide sodium hydroxide solution using platinum electrodes?

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Which of the following statements is true? When the potassium atom forms its ion

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A gas occupies 30.0 dm³ at S.T.P. What volume would it occupy at 91^oC and 380 mm Hg?

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Which are the correct IUPAC names for H-CO₂CH₃ and CH = CH

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Which of the following contains two amphoteric oxides?

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Bronze is an alloy of

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The oxidation state of manganese in potassium permanganate is

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If chlorine gas is bubbled into water and then this yellowish-green coloured solution is exposed to bright sunlight for a while

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Which of the following statements is true?

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0.1 Faraday of electricity was passed through a solution of copper (ll) sulphate. The maximum weight of copper deposited on the cathode would be [Cu = 64]

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When carbondioxide is bubbled into limewater a white precipitate is formed. If the passage of the gas is continued, the precipitate disappears. The reason for this is

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When a piece of charcoal enclosed in a cylinder containing air is ignited

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Calcium hydroxide and ammonium chloride when heated together will give an important product. This compound may be obtained dry by

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The empirical formula of an oxide of nitrogen containing 30.4 per cent of nitrogen is (N=14.0,O=16.0)

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Starch can be converted to ethyl alcohol by

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Which of the following raw materials would be required from the smelting of iron ore in a blast furnace?

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An anhydride is

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Phosphorus burns in oxygen according to the equation P₄ + 50₂ → P₄O₁₀. How many litres of oxygen will be required at S.T.P for complete oxidation of 12.4g of phosphorus? [P = 31,O = 16 and molar volume of a gas at S.T.P = 22.4 litres]

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12 g of solid protassium chlorate (KCIO) were added to 40 g of water and heated to dissolve all the solid. As the solution cools, crystals of potassium chlorate at 66 ^oC. The solubility of potassium chlorate at 66 ^oC is therefore

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Two metallic ions associated with hard water are

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Which of the structural formal above is ethanoic acid is

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Indicate which of the following statements is not true as we move from left to right along the periodic Table:

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In the electrolysis of dilute sulphuric acid using platinum electrodes, the products obtained at the anode and cathode are:
Anode Cathode

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\(50cm^{3}\) of hydrogen are sparked with \(20cm^{3}\) of oxygen at \(100°C\) and \(1atm\) . The total volume of the residual gases in

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The reaction of zinc with copper (ll) ions in aqueous solution can be represented as follows: Cu ²⁺(aq) +Zn (s) → Cu(s) + Zn ²⁺(aq).Which of the following is the most complete description of this reaction?

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Pick out the correct statement

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The IUPAC name for

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Which of the following substances are all made by the process of polymerization?

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An organic compound X has the following properties: I. It is not miscible with water. ll. lt has boiling point of 77^oC lll. lt has a sweet odour lV. lt is insoluble in sodium hydrogen carbonate solution . V lt does not decolourize bromine water X is therefore

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The reaction between hydrogen and iodine may be represented by the equation H₂(g)+ I₂(g) → 2HI(g), and is exothermic. Therefore

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In the manufacture of iron in the blast furnace, iron (lll) oxide is mixed with coke and limestone, and different reactions occur in the process. Which of the following statements is true with respect to these reactions?

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Hydrogenation may be effected by

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How many grams of HBr would exactly be required to react with 2 g of propyne? (C =12, H=1, Br = 80)

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