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QUESTION 11 Determine the colour of a solution with a pH of 9.6 containing bromocresol green indicator. (A) pink (B) blue (C) green (D) yellow
QUESTION 22 (7 marks) The structures of phenol red when in either an acidic or a basic solution are shown in the equation. on 0 OHÔøΩ OO am & OTs Ht Se se Yellow Red a) Identify the species that acts as the conjugate base by circling it in the equation. [1 mark] Note: If you make a mistake draw a line through this equation and use the additional equation provided on page 13 of this question and response book. b) A solution of phenol red at equilibrium and 50 ÔøΩC was found to contain 2.0 x 10-4 M of the conjugate base and 0.034 M of the acid. Determine the pK for the system assuming all the protons present come from dissociation of the acid. [3 marks] (to two significant figures) c) Explain the relationship between the pH range of phenol red and its pK value. [3 marks]
QUESTION 10 The midpoint of the colour change of a weak acid indicator occurs when (A) [In-]=[H ] (B) [In] =[HIn] (C) [H*]=[OH ] (D) [HIn]=[OH ]
QUESTION 27 (5 marks) Five colourless 0.1 M solutions of NH3 HCl KOH H SO and CH;CH COOH have lost their labels. The substances are randomly relabelled A B C D and E. The conductivity of each solution and the colour of the solution when phenol red was added are shown. Solution | Conductivity (S/m) Colour with phenol red ec es ee Identify the five solutions. Explain your reasoning
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