(a) State an indicator suitable for the titration of;
(i) dilute HCl and NaOH\(_{3(aq)}\)
(ii) dilute CH\(_3\)COOH and KOH\(_{(aq)}\)
(iii) dilute HCl and NH\(_{3(aq)}\).
Give a reason for your answer in each case.
(b) Calculate the volume of water that would be added to 50 cm\(^3\) of 0.10 mol dm\(^{-3}\) of HCI to dilute it to 0.010 mol dm \(^{-3}\)
(c) Name one gas that could be used to demonstrate the fountain experiment.
Explanation
(a)(i) Phenolphthalein or methyl orange or methyl red. Titration of strong acid and strong base.
(ii) Phenolphthalein reasons; Titration of a weak acid and strong base
(iii) Methyl orange or Methyl red reason: Are strong acid and weak base
(b) Using dilution law;
C\(_1\)V\(_1\) = C\(_2\)V\(_2\)
0.1 x 50 = 0.010 x V\(_2\)
V\(_2\) = \(\frac{0.1 \times 50}{0.010}\) = 500 cm\(^3\)
Volume of distilled water to be added to the original solution to make 0.01 mol/dm\(^3\)
= 500 - 50
= 450 cm\(^{3}\)
(c) Hydrogen chloride gas or ammonia or sulphur (IV) oxide