Acids, Alkalis and Salt prep

Question 1

Describe how to carry out titration

Answer 1

• rinse the conical flask with (alkali).
• rinse the burette with
  (distilled water).
• add (acid) to the burette and record the initial burette reading.
• use a pipette to measure volume of (alkali) and transfer to the conical flask.
• add a few drops of phenolphthalein indicator to the conical flask.
• add (acid) from the burette until the solution turns colourless permanently.
• swirl the conical flask.
• add (acid) dropwise close to the end point.
• record final burette reading
• repeat the titration to obtain concordant results

Question 2

Solubility rule

Answer 2

• all nitrates are soluble
• all gp 1 are soluble
• all ammonium are soluble
• all sulfates are soluble except from lead, silver, barium and calcium
• all halides are soluble except from lead and silver
• most carbonates are insoluble except from gp1 and ammonium
• most metal hydroxides are insoluble except from gp1 and ammonium, calcium is slightly soluble

Question 3

Making soluble salts

Answer 3

Titration for gp1 and ammonium
Adding excess solid for others

Question 4

Making insoluble salts

Answer 4

Precipitation

Question 5

Describe steps for obtaining soluble salt from add excess solid

Answer 5

• warm the acid in a beaker gently using a Bunsen burner (to increase the rate of reaction)
• add base to acid until in excess (to make sure all acid is used up)
• stir the mixture (to make sure that no more will react)
• filter off the excess solid
• heat the solution until it becomes saturated
• leave it to cool slowly and crystallise
• remove the crystals by filtration
• dry them in between filter paper or leave in a warm place