Year :
2003
Title :
Chemistry
Exam :
NECO - BECE
Paper 1 | Objectives
21 - 30 of 38 Questions
| # | Question | Ans |
|---|---|---|
| 21. |
What change will occur during the electrolysis of brine using carbon electrodes? A. Chlorine will be given off at the cathode B. Oxygen gas will be given off at the anode C. Sodium will be deposited at the cathode D. The resulting solution, after electrolysis, will be acidic. E. The volumes of hydrogen and chlorine given off during the same time are equal Detailed SolutionChlorine is discharged as follows:\(Cl^- \to Cl + e^-\) \(Cl + Cl \to Cl_{2(g)}\) This reaction occurs at the anode. |
|
| 22. |
Which metal bromide is widely used in photography? A. calcium bromide B. magnesium bromide C. potassium bromide D. silver bromide E. sodium bromide |
D |
| 23. |
How many Faradays of electricity are required to liberate 9g of aluminium? [Al = 27] A. 0.1 B. 0.3 C. 1 D. 2.7 E. 3 |
C |
| 24. |
At s.t.p, a mole of chlorine occupies 22.4dm3. If the temperature is changed to 35°C and the pressure to 750mHg the of the new volume will be [Cl = 35.5] A. \( ^{\text{760 x 22.4 x 308}} \text{750 x 273x 35.5} dm^3 \) B. \( ^{\text{760 x 22.4 x 308}} \text{750 x 273}^x dm^3 \) C. \( ^{\text{750 x 22.4 x 35.5}} \text{760 x 273dm3} \) D. \( ^{\text{760 x 22.4 x 35.5}} \text{750x22.3x273} \) E. \( ^{\text{760 x 22.4 x 35.5}} \text{750 x 308dm3} \) |
B |
| 25. |
What is the concentration (in mol dm3) of a solution containing 28 g of potassium hydroxide per 100 cm3 of solution? (K=39; H=1; 0=16) A. 0.01 B. 0.05 C. 0.1 D. 0.5 E. 2.8 |
B |
| 26. |
Which method is used for the purification of copper from its ore? A. distillation B. electrochemical C. electrolysis D. neutralization E. reduction |
C |
| 27. |
Ethene decolourises acidified potassium tetraoxomanganate(VII) solution. Which gas will decolourise bromine water? A. CH4 B. C2H6 C. C3H6 D. C3H8 E. C6H6 |
C |
| 28. |
What is formed when starch is completely hydrolysed? A. fructose B. glucose C. lactose D. maltose E. sucrose |
B |
| 29. |
Which hydrocarbon does NOT exhibit structural isomerism? A. C3H6 B. C4H6 C. C4H8 D. C4H10 E. C5H12 Detailed SolutionAlkenes that show structural isomerism are those with 4 carbons and above. |
|
| 30. |
Why is tetraoxosulphate(VI) acid NOT used for making carbon dioxide from calcium carbonate? It is A. a dehydrating agent B. a strong acid C. an oxidising agent D. dibasic E. forms insoluble calcium tetraoxosulphate(Vl) |
E |
| 21. |
What change will occur during the electrolysis of brine using carbon electrodes? A. Chlorine will be given off at the cathode B. Oxygen gas will be given off at the anode C. Sodium will be deposited at the cathode D. The resulting solution, after electrolysis, will be acidic. E. The volumes of hydrogen and chlorine given off during the same time are equal Detailed SolutionChlorine is discharged as follows:\(Cl^- \to Cl + e^-\) \(Cl + Cl \to Cl_{2(g)}\) This reaction occurs at the anode. |
|
| 22. |
Which metal bromide is widely used in photography? A. calcium bromide B. magnesium bromide C. potassium bromide D. silver bromide E. sodium bromide |
D |
| 23. |
How many Faradays of electricity are required to liberate 9g of aluminium? [Al = 27] A. 0.1 B. 0.3 C. 1 D. 2.7 E. 3 |
C |
| 24. |
At s.t.p, a mole of chlorine occupies 22.4dm3. If the temperature is changed to 35°C and the pressure to 750mHg the of the new volume will be [Cl = 35.5] A. \( ^{\text{760 x 22.4 x 308}} \text{750 x 273x 35.5} dm^3 \) B. \( ^{\text{760 x 22.4 x 308}} \text{750 x 273}^x dm^3 \) C. \( ^{\text{750 x 22.4 x 35.5}} \text{760 x 273dm3} \) D. \( ^{\text{760 x 22.4 x 35.5}} \text{750x22.3x273} \) E. \( ^{\text{760 x 22.4 x 35.5}} \text{750 x 308dm3} \) |
B |
| 25. |
What is the concentration (in mol dm3) of a solution containing 28 g of potassium hydroxide per 100 cm3 of solution? (K=39; H=1; 0=16) A. 0.01 B. 0.05 C. 0.1 D. 0.5 E. 2.8 |
B |
| 26. |
Which method is used for the purification of copper from its ore? A. distillation B. electrochemical C. electrolysis D. neutralization E. reduction |
C |
| 27. |
Ethene decolourises acidified potassium tetraoxomanganate(VII) solution. Which gas will decolourise bromine water? A. CH4 B. C2H6 C. C3H6 D. C3H8 E. C6H6 |
C |
| 28. |
What is formed when starch is completely hydrolysed? A. fructose B. glucose C. lactose D. maltose E. sucrose |
B |
| 29. |
Which hydrocarbon does NOT exhibit structural isomerism? A. C3H6 B. C4H6 C. C4H8 D. C4H10 E. C5H12 Detailed SolutionAlkenes that show structural isomerism are those with 4 carbons and above. |
|
| 30. |
Why is tetraoxosulphate(VI) acid NOT used for making carbon dioxide from calcium carbonate? It is A. a dehydrating agent B. a strong acid C. an oxidising agent D. dibasic E. forms insoluble calcium tetraoxosulphate(Vl) |
E |