(a) Name one laboratory equipment used for
(i) keeping salts dry:
(ii) converting vapour to liquid during distillation
(ii) bubbling a gas into a liquid
(b) (i) What technique would you use to purify a sample of sodium chloride contaminated with ammonium chloride?
(ii) Given sodium hydroxide solution, outline the procedure you would use to determine whether or not all the ammonium chloride in (b)(i) above had been removed.
(c) State what is observed on carrying out each of the following exercises.
(i) Adding few drops of methyl orange indicator to lime juice:
(ii) Adding few drops of concentrated HNO\(_3\) to acidified FeSO\(_4\) solution
(iii) Exposing a fresh precipitate of silver chloride to sunlight for 30 minutes
(iv) Adding zinc dust to dilute CuCl\(_2\) solution;
(v) Adding dilute H\(_2\)SO\(_4\), to Pb(NO\(_3\))\(_2\) solution
Explanation
(a)(i) desiccator
(ii) Liebig condenser
(iii) Delivery tube
(b)(i) Sublimation
(ii) Make a small solution of the salt, add NaOH dropwise and then excess. If there is no visible reaction, even when warmed, it indicates that the whole ammonium chloride has sublimed. But if a gas with choking or irritating smell which turns red litmus paper blue is given off then it's the ammonium salt.
(c)(i) The colour turns red/ pink
(ii) A brown ring is formed where the HNO\(_3\) gets in contact with the acidified FeSO\(_4\).
(iii) It turns violet and then black
(iv) Copper is deposited.
(v) A white precipitate will be formed.