All your burette readings (initials and final) as well as the size of your pipette must be recorded but no account of experimental procedure is required. All calculations must be done in your answer booklet

(a) What difference in physical properties enable the separation of mixtures by:

(i) simple distillation,

(ii) paper chromatography;

(iii) fractional distillation.

 

(b) Give a reason for each of the following practices during titration in the laboratory.

(i) White tile is placed under the conical flask.

(ii) Burette readings are always recorded to two decimal places.

(iii) Calculate the volume of 2.5 moldm\(^{-3}\) stock HČI required to prepare 500 cm\(^3\) of 0.20 moldm HCI.