A graduated diagram represents a pH scale with values P1, P2, P3, P4. What do these pH values indicate about acidity/alkalinity? Give examples and describe litmus paper reactions. Also, identify farm

c) The graduated diagram below represents a pH scale.

i) Read and record each of the pH values; P1, P2, P3 and P4

• P1: $\boxed{2}$
• P2: $\boxed{6}$
• P3: $\boxed{7}$
• P4: $\boxed{13}$

ii) What does pH; P1 and P2 indicate. Give one example of such liquid
pH values P1 (2) and P2 (6) indicate that the liquids are acidic.
Example of a liquid with pH 2: Lemon juice or stomach acid.
Example of a liquid with pH 6: Milk or urine.

iii) What does pH; P3 and P4 indicate. Give one example of such liquid
pH value P3 (7) indicates that the liquid is neutral.
Example of a liquid with pH 7: Pure water.
pH value P4 (13) indicates that the liquid is strongly alkaline (basic).
Example of a liquid with pH 13: Sodium hydroxide solution or drain cleaner.

iv) State the observations red litmus and blue litmus paper are dipped in turns into each of the liquid

• P1 (pH 2 - strong acid): Red litmus remains red. Blue litmus turns red.
• P2 (pH 6 - weak acid): Red litmus remains red. Blue litmus turns red.
• P3 (pH 7 - neutral): Red litmus remains red. Blue litmus remains blue.
• P4 (pH 13 - strong base): Red litmus turns blue. Blue litmus remains blue.

d) The diagrams below represent farm tools.

i) Write the names of the devices A and B

• Device A: Knapsack sprayer (or Backpack sprayer)
• Device B: Watering can

ii) Label the parts N, P, Q, R, S, T and U

• N: Tank / Container
• P: Hose / Delivery tube
• Q: Pump / Piston / Pressure chamber
• R: Lance / Spraying rod
• S: Nozzle
• T: Rose / Sprinkler head / Spout
• U: Handle

iii) State one use each of the two devices

• Device A (Knapsack sprayer): Used for applying pesticides, herbicides, or foliar fertilizers to crops.
• Device B (Watering can): Used for watering plants, especially seedlings or potted plants.

iv) State the use of the parts labelled Q
Q is the pump/piston/pressure chamber. Its use is to build pressure to force the liquid from the tank through the hose and out the nozzle as a fine spray.

v) State one similarity between device A and B

• Both devices are used for dispensing liquids.
• Both have a container to hold the liquid.
• Both have a spout/nozzle for directing the liquid.