Testing unknown solutions.

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Helen Spencer, candidate number: 9326, centre number: 55245

Chemistry Practical Test (Part A): Planning Exercise

Testing unknown solutions


In this practical investigation, I have to devise a logical sequence of chemical reactions to find out which unknown chemical goes with which name. I then have to outline a titration procedure for working out the exact concentration of aqueous nitric acid using aqueous sodium carbonate, concentration of 0.500 mol dm¯³

Precautions – Health and Safety

  • Wear safety glasses
  • Handle all chemicals with care
  • Wash hands before and after handling and chemicals
  • Have an eye wash available.


Test tubes,

Small pipette,

Calcium carbonate (marble chips),

Dilute hydrochloric acid,

Silver nitrate,

Nitric acid,

Aqueous ammonia solution,

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Delivery tube and stopper,

Bunsen burner,

Safety mat,

Test tube holder


  1. Testing for calcium hydroxide:

Carbon dioxide bubbled through calcium hydroxide gives a milky white precipitate, calcium carbonate.

Ca(OH)2 (aq)  +  CO2 (g)                      CaCO3 (s)  +  H2O (l)

Calcium hydroxide  +  carbon dioxide             calcium carbonate  +  water 

  1. testing for potassium bromide and sodium chloride:

  • Both bromide and chloride are halide ions
  • They both react with ...

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