(a)(i) List two physical properties used as criteria for purity of substances

(ii) describe how you would prepare a pure, dry sample of sodium chloride crystals by a neutralization reaction, using bench reagents.

(iii) Give two other general methods for preparing soluble salts.

 

(b) Explain the following observations:

(i) a sheet of iron placed in dilute copper (II) tetraoxosulphate (VI) solution reddish brown;

(ii) the white gelatinous precipitate formed when a few drops of sodium hydroxide solution are added to a solution of aluminium salt dissolves in excess alkali;

(iii) the pale green prepared iron(II) chloride solution changes to brown on bubbling chlorine gas through it.

(iv) Write a balanced equation for the reaction of dilute hydrochloric acid with marble. List two industrial process in which limestone is used as a raw material.