Disinfecting Household Articles

21 Grade 9 Agriculture questions on Disinfecting Household Articles, with worked marking schemes. 21 questions are available on this topic in full.

1. Question 1

   1 mark

   After a family member recovered from a contagious illness, a learner is asked to disinfect the used utensils and surfaces. Why is disinfecting important here, compared to ordinary washing?

   A. It makes the items shinier

   B. It kills disease-causing micro-organisms that washing may leave behind

   C. It dries the items faster

   D. It changes the colour of the items

   (1 mark)

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2. Question 2

   1 mark

   Before applying a disinfectant to a dirty kitchen chopping board, the FIRST step should be to:

   A. Wrap the board in a plastic bag

   B. Store the board in a cupboard

   C. Rub the board with dry soil

   D. Wash off visible dirt and food remains with soap and water

   (1 mark)

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3. Question 3

   4 marks

   Explain why each of the following is important when disinfecting household articles.

   (a) Cleaning the article before applying the disinfectant. (2 marks)

   (b) Observing the recommended contact time. (2 marks)

   (4 marks)

   Marking scheme

   (a) Cleaning removes dirt, grease and food remains that would shield micro-organisms and reduce the disinfectant's effectiveness, so the disinfectant can reach and act on the germs (2 mks). (b) The disinfectant needs enough time in contact with the surface to kill the micro-organisms; rinsing too soon leaves germs alive and makes the treatment ineffective (2 mks).

4. Question 4

   1 mark

   After a family member recovers from a stomach illness, a learner is asked to disinfect the cups, plates and cutlery they used. Which method effectively disinfects these household articles?

   A. Wiping them with a dry cloth only

   B. Washing them and then immersing in boiling water or a recommended disinfectant solution

   C. Rinsing them in cold water once

   D. Storing them dirty until the next day

   (1 mark)

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5. Question 5

   1 mark

   A learner reads that a disinfectant must be used at the correct dilution stated on the label. Why is it important NOT to use a disinfectant at a stronger concentration than recommended when treating household articles?

   A. Stronger concentrations always kill fewer germs

   B. It can leave harmful residues, damage articles and waste the product without extra benefit

   C. Disinfectants only work when diluted with milk

   D. A stronger solution makes the articles dirtier

   (1 mark)

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6. Question 6

   1 mark

   Which of the following would MOST likely reduce the effectiveness of a disinfectant applied to a household surface?

   A. Leaving heavy dirt and grease on the surface before applying it

   B. Using the correct dilution

   C. Allowing the disinfectant enough contact time

   D. Cleaning the surface first with soap

   (1 mark)

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7. Question 7

   1 mark

   After disinfecting utensils with a chemical solution, they should be air-dried on a clean rack mainly to:

   A. Avoid recontamination from a dirty drying cloth

   B. Make them rust quickly

   C. Add germs back onto them

   D. Keep them permanently wet

   (1 mark)

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8. Question 8

   1 mark

   A learner prepares a chlorine-based solution to disinfect cutting boards at home but is concerned about safety. Which precaution should the learner observe?

   A. Mix the chlorine solution with ammonia for a stronger effect

   B. Use the correct dilution and ensure good ventilation while working

   C. Use the most concentrated solution undiluted on all surfaces

   D. Apply it to food directly before eating

   (1 mark)

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9. Question 9

   4 marks

   A family wants to disinfect their kitchen utensils and chopping boards to prevent food-borne diseases.

   (a) State two reasons why household articles should be disinfected. (2 marks)

   (b) Describe two methods they can use to disinfect the utensils. (2 marks)

   (4 marks)

   Marking scheme

   (a) Any 2 (1 mk each): to kill disease-causing micro-organisms; to prevent spread of infections and food poisoning; to keep the home hygienic. (b) Any 2 (1 mk each): boiling the utensils in water (using heat); soaking or wiping with a chemical disinfectant such as diluted bleach at the correct dilution, then rinsing and air-drying.

10. Question 10

    1 mark

    Allowing a disinfectant to remain on a surface for the recommended contact time before rinsing is important because it:

    A. Wastes the disinfectant

    B. Makes the surface dirtier

    C. Cools the surface down

    D. Gives the chemical enough time to kill the micro-organisms

    (1 mark)

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11. Question 11

    1 mark

    Which household articles should be given PRIORITY for regular disinfection to prevent the spread of disease?

    A. Curtains in a spare room

    B. Toilet handles, utensils and door knobs

    C. Garden ornaments

    D. Framed wall photographs

    (1 mark)

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12. Question 12

    4 marks

    Outline the correct procedure for disinfecting a dirty kitchen chopping board using a chemical disinfectant. (4 marks)

    (4 marks)

    Marking scheme

    Any 4 steps in order (1 mk each): wash off visible dirt and food remains with soap and clean water; prepare the disinfectant at the correct dilution as per the label; apply or soak the board and leave it for the recommended contact time; rinse with clean water where required; air-dry on a clean rack. Award for a logical sequence.

13. Question 13

    3 marks

    Differentiate between cleaning and disinfecting a household article, and state why both are usually needed. (3 marks)

    (3 marks)

    Marking scheme

    Cleaning is the removal of visible dirt, grease and food remains using water and detergent (1 mk); disinfecting is the use of heat or chemicals to kill disease-causing micro-organisms (1 mk). Both are needed because cleaning removes dirt but not all germs, while disinfecting kills germs but works best on an already clean surface (1 mk).

14. Question 14

    1 mark

    Which of the following household articles is MOST appropriately disinfected by boiling in water rather than soaking in bleach?

    A. Wooden furniture

    B. Woollen blankets

    C. Electrical kettles while plugged in

    D. Metal cooking spoons and feeding bottles

    (1 mark)

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15. Question 15

    1 mark

    A common and cheap household disinfectant used to treat surfaces is a solution of:

    A. Cooking oil

    B. Fresh milk

    C. Sugar

    D. Sodium hypochlorite (bleach)

    (1 mark)

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16. Question 16

    4 marks

    When using chemical disinfectants in the home, safety precautions must be observed. State four safety precautions to observe when handling household disinfectants. (4 marks)

    (4 marks)

    Marking scheme

    Any 4 (1 mk each): follow the label instructions and correct dilution; wear protective gloves to protect the skin; work in a well-ventilated area; do not mix different chemicals or disinfectants; store in clearly labelled containers away from food and out of reach of children; wash hands after use; keep away from the eyes and mouth.

17. Question 17

    1 mark

    Disinfecting household articles such as feeding utensils and cutting boards is important mainly because it:

    A. Kills disease-causing micro-organisms and prevents infections

    B. Makes the articles rust faster

    C. Increases the weight of the articles

    D. Adds a shiny colour to the articles

    (1 mark)

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18. Question 18

    1 mark

    When using a chemical disinfectant, following the correct dilution rate on the label is important because:

    A. Dilution only changes the colour

    B. Too weak may not kill germs while too strong may be harmful

    C. The dilution has no effect on the result

    D. A stronger dose always cleans faster and is safe

    (1 mark)

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19. Question 19

    1 mark

    Wearing gloves when handling strong household disinfectants is recommended mainly to:

    A. Make the work look professional

    B. Keep the hands warm

    C. Protect the skin from irritation and chemical burns

    D. Improve grip on wet surfaces only

    (1 mark)

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20. Question 20

    1 mark

    A safety precaution to observe when using chemical disinfectants at home is to:

    A. Mix bleach and other cleaners for a stronger effect

    B. Store them in unlabelled food containers

    C. Drink a little to test the strength

    D. Work in a well-ventilated area and avoid mixing different chemicals

    (1 mark)

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21. Question 21

    1 mark

    Boiling household articles such as babies' feeding bottles in water for a few minutes is a method of:

    A. Fertilising

    B. Fermentation

    C. Ventilation

    D. Disinfection using heat

    (1 mark)

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