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Questions 5.2b

  1. Describe what is observed when calcium metal is added to water. ----------
  2. Reactions between metals and water produce similar products. Name the products of reaction between calcium and water. ----------------------
  3. How would the solution formed affect litmus paper? ---------------------
  4. The same gas is produced in the reactions involving potassium and sodium.
    Write equations for the reactions between
    1. Potassium and water ------------------------------------
    2. Sodium and water ------------------------------------------
    3. Calcium and water ------------------------------------
  5. Complete the following general equation for the reactions between metal and water.
  6. Arrange the three metals in the order of their reactivity with water, beginning with the most reactive.


Answers to Questions 5.2b

  1. Vigorous effervescence (production of colourless gas bubbles) and a colourless solution that turns phenolphthalein solution pink. The gas extinguishes a burning splint with a pop sound.
  2. Calcium hydroxide solution and hydrogen gas.
  3. The solution would turn red litmus blue.

  4. Potassium + Water   ⟶   Potassium hydroxide + Hydrogen
    Sodium + Water   ⟶   Sodium hydroxide + Hydrogen
    Calcium + Water   ⟶   Calcium hydroxide + Hydrogen

  5. Metal + Water   ⟶   Metal hydroxide + Hydrogen

  6. Potassium, Sodium, Calcium