CHEMISTRY PAST QUESTIONS

Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode?

Which of the following substances decomposes when an electric current is passed through it?

Dehydration of ethanol produces

What mass of copper would be deposited by a current of 1. 0 ampere passing for 965 seconds through copper (ll) tetraoxosulphate (IV) solution? [Cu = 63.5; 1F = 96500C]

Which of the following will displace copper from a solution of copper (ll) salt?

Consider the reaction represented by the following equation: H_2(g) + 1_2(g) → 2HI_(g). The number of effective collisions of molecules of the reactants decreases as

A concentrated solution containing H⁺, Cu²⁺,OH^- and CI^- was electrolysed using platiunm electrodes which of the ions will be discharged at the cathods?

Which of the following can undergo both addition reactions and substitution reactions?

What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO₃?

What will be the effect of increase in pressure on the following system at equilibrium? 2NH_2(g) N_2(g) + 3H_2(g)

Pipe-borne water is usually chlorinated in order to

Which of the following non-metals reacts most readily with metals?

Which of the following methods is suitable for the preparation of an insoluble salt?

Elements which belong to the same group in the Periodic Table are characterized by

Calcium atom ionizes by

Rusting of iron is an example of

The liquid product of the destructive distillation of coal is

Two radioactive elements Q and S have half-life periods of 10 hours and 20 hours respectively. Therefore

What is responsible for metallic bonding?

The property of calcium chloride which makes it useful as a drying agent is that it is

An exothermic reaction is one which involves

Petrol consists mainly of

Gas molecules are said to be perfectly elastic because

What is oxidized in the reaction represented by the following equation? 3CU + 8HNO₃ → 3Cu(NO₃)₂ + 2NO + 4H₂O

A reaction is represented by the equation below. A_2(g) + B_2(g) 2AB_(g); ∆H = +X kJmol^-1 Which of the following statements about the system is correct?

What is the shape of a molecule of CCI₄?

Chlorine atom forms CI by

What is the effect of using vanadium (V) oxide as catalyst in the reaction represented by the following equation? 2SO₂ + O₂ ⇌ 2SO₃; ∆H = - xKJmol-¹

Electrovalent compounds are characterized by

One mole of a compound M(HCO₃)₂ has a mass of 162g. Calculate the relative atomic mass of M. [H = 1, C =12, O = 16]

It can be concluded that gastric juice

The spontaneity of a chemical reaction is determined by the change in the

30cm³ pf hydrogen at s.t.p combine with 20cm³ of oxygen to form steam according to the following equation 2H_2(g) + O_2(g) → 2H₂O_(g). Calculate the total volume of the gaseous mixture at the end of the reaction

Which of the following movements can be described as random motion?

Given that the order of reactivity of four metals is P>Q>R>S, which of the following reactions is feasible?

How many electrons are removed from Cr^2- when it is oxidized to CrO₄^2-?

What does ∆H represent in the following equation ? Cl_(g) + e- → CI- _(g); ∆H = - 363 kJ mol-¹

Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of

0.10 mol dm^-3 NaCI conducts electricity better than 0.10 mol dm^-3 CH₃COOH because the solution of NaCI

Which of the following compounds dissolves in water to give an alkaline solution?

Helium is preferred to hydrogen in filling balloons because hydrogen

Which of the following pairs of reagents recat to produce hydrogen?

Which of the following contains co-ordinate covalent bond?

In the Periodic Table, the elements that loss electrons most readily belong to

Which of the following would dissolve in warm dilute H₂SO₄ without effervescence, to give a blue solution?

Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy?

What is the oxidation number of nitrogen in AI(NO₃)₃?

Which of the following statements about ideal gases is/are correct?

I. The cohesive forces between their particles are negligible

ll. The have no definite volume but occupy the volume of their containers

III. They are not compressible

IV. Their particles collide with loss of energy

What is the value of x in the following equation? Cr₂O₇^2- + 14H⁺ + xe- → 2Cr³⁺ + 7H₂O

Consider the following equation: Ag⁺ _(aq) + CI-_(aq) → Ag⁺CI- _(s) ; ∆H = _65.7 kJmol^-1. From the equation, it can be deduced that

Metals are said to be malleable because they

If an element with high electron affinity combines with another element with low ionization energy the bond formed will be mainly

When alkanols react with sodium, the ga evolved is

P _Total = F₁ + P₂ + P ₃ + .........P_n' where P _Total is the pressure of a mixture of gasses. The equation above is an expression of

Substances which absorb water from the atmosphere without dissolving in it are said to be

Chemical equilibrium is attained when

Which of the following compounds dissolves in water to form a solution with pH below 7?

The presence of unpaired electrons in an atom of a transition metal gives rise to

What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn_(s) + 2HCI_(aq) → ZnCI _2(aq) + H_2(g) [Zn = 65; 1 mole of a gas occupies 22.4dm³ at s.t.p]

The type of chemical bond that exists between potassium and oxygen in potassium oxide is