Past Questions And Answers

4541

Nigeria is NOT a member of the

A. Non-Aligned Nations
B. Organization of Petroleum Exporting Countries
C. Organization for Economic Cooperation and Development
D. International Monetary Fund

View Discussion (0)JAMB 1991

4542

Multi-party system is saddled with the problem of

A. divisiveness
B. limited choice
C. weak opposition
D. political consciousness

View Discussion (0)WAEC 2022 OBJ

4543

Under the ECOWAS agreement, a Nigerian can enter and stay in Ghana without a visa for a period of

A. 14 days
B. 30 days
C. 60 days
D. 90 days 100 days

View Discussion (0)WAEC 1994 OBJ

4544

(a)(i) Define the term standard electrode potential.

(ii) State three factors that affect the discharge of ions during electrolysis.

(iii) State two functions of a salt bridge in an electrochemical cell.

(b) Describe briefly what happens when a solution of copper (II) tetraoxosulphate (VI) is electrolyzed using copper electrodes.

c) Calculate the mass of copper deposited at the cathode when a current of 0.2A is passed through a solution of copper (II) tetraoxosulphate (VI) for 35 minutes using copper electrodes. [H = 1.00, O = 16.0, S = 32.0, Cu = 64.0, IF = 96,500C]

(d)(i) State three characteristics of a catalyst.

ii) Name one manufacturing process in which each of the following metals is used as catalyst: I. iron; II. nickel; Ill. platinum.

Explanation

(a)(i) Define the term standard electrode potential: It is the measure of the tendency of an element to form ions in solution relative-to the tendency of hydrogen atoms to form ions in solution at standard condition/ the potential difference that exists between an electrode and the hydrogen electrode under standard conditions (of I moldm\(^{-3}\) concentration at 298k and 1 atm).

(ii) State three factors that affect the discharge of ions during electrolysis: (1) Position of ions in the electrochemical series/standard electrode potential value. (2) Nature or reactivity of electrode used. (3) (relative) concentration of ions.

(iii) State two functions of a salt. bridge in an electrochemical cell: (1) Allows electrical contact between two solutions/complete the electric circuit (2) Maintains electrical neutrality in each half cell/allows ions flow in and out of salt bridge.

(b)(i) Describe briefly what happens when a solution of copper(II) tetraoxosulpahte(VI) is electrolysed using copper electrodes:

CuSO\(_4\) \(\rightleftharpoons\) Cu\(^{2+}\) + SO\(_4^{2-}\); Cu\(^{2+}\) discharged/Cu metal deposited/Cu cathode increases in mass.

H\(_2\)O \(\rightleftharpoons\) H\(+\) + OH\(-\) Copper anode dissolves/ionizes/decreases in size to give Cu\(^{2+}\) ions.

Solution remains blue/concentration of Cu\(^{2+}\) ions is constant.

(c) Calculate the mass of copper(II)tetraoxosulphate(V1) for 35 minutes using copper electrodes:. [H=1, O=16, S=32, Cu=64, IF=96,500]

Cu\(^{2+}\) + 2e ---> Cu

Q = It = 0.2 x 35 x 60 = 420C

2F = 2e = 1mole \(\frac{Cu}{2}\) x 96500C = 64g

420C = \(\frac{420}{ 2 x 96500}\) x 64gCu

= 0.14gCu.

(d)(i) State three characteristics of catalyst: (1) Remains unchanged in chemical nature and mass. (2) Does not affect the types of product formed. (3) Alters (increase or decrease) the rate of chemical reaction. (4) They are reactions specific. (5) Cannot initiate a reaction that is not feasible. (6) Has no effect on the equilibrium of a reversible reaction. (7) Required in small quantity.

(ii) Name one manufacturing process in which each of the following metals is used as a catalyst:

I. Iron – used in Haber process.

II. Nickel – hydrogenation of vegetable oil/alkenes.

III. Platinum – used in preparation of hydrogen iodido from hydrogen and iodine/contact process for H\(_2\)SO\(_4\) production/manufacture of HNO\(_3\) used in Hydrogenation.

View Discussion (0)WAEC 2013 THEORY

4545

An example of an acidic oxide is

A) NO
B) CO
C) SO2
D) CuO

View Discussion (0)JAMB 2016

4546

Which of the following is a way of preventing drug traficking?

A. foreign scholarship
B. employment
C. motivation
D. indulging offenders

View Discussion (0)WAEC 2018 OBJ

4547

A system of government where the ultimate power resides in the people is

A. plutocracy
B. aristocracy
C. theocracy
D. democracy

View Discussion (0)WAEC 2021 OBJ

4548

One of the functions of a Party Whip in the Legislature is to

A. punish erring members of the party in the House
B. ensure that members are present during important sessions
C. ensure that the House is properly dissolved
D. lead the minority party in the House debate

View Discussion (0)WAEC 2005 OBJ

4549

An element of nucleon number P and atomic number Q emits an alpha particle from its nucleus. The resultant numbers of the new element formed are respectively

A. P - 4 and Q + 2
B. P - 4 and Q - 2
C. P + 2 and Q + 2
D. P + 2 and Q - 2

View Discussion (0)WAEC 2014 OBJ

4550

Which of the following best describes a colony of volvox?

A. Asexually reproduced cells held together in a mass, but independent of each other
B. Sexually reproduced cells held together in a mass, and dependent on each other
C. Single free-living acellular units irrespective of their parental origin
D. Several units of cells, held together by cytoplasmic strands and dependent on each other

View Discussion (0)WAEC 2000 OBJ

Past Questions And Answers

Correct Answer: C. Organization for Economic Cooperation and Development

Correct Answer: A. divisiveness

Correct Answer: D. 90 days 100 days

Explanation

Correct Answer: C) SO2

Correct Answer: B. employment

Correct Answer: D. democracy

Correct Answer: B. ensure that members are present during important sessions

Correct Answer: B. P - 4 and Q - 2

Correct Answer: A. Asexually reproduced cells held together in a mass, but independent of each other