Edexcel Jun 2015 (IAL) Paper 6 Q2

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2 A salt, P, contains carbon, hydrogen, oxygen and one metallic element. (a) When a flame test is carried out on P, a yellow flame results. Give the formula of the metal ion in the salt. (1)(b) P dissolves in water to form a weakly alkaline solution, Q, with pH 8.1. The pH of Q can be measured by using a calibrated pH meter or an indicator. (i) Describe how to calibrate a pH meter. (2)(ii) Name a suitable indicator you could use and state the colour you would expect to observe. (2)(iii) Which of the two methods will give the more accurate value for the pH of Q? Justify your answer. (1)*P44884A0316* Turn over<br /> (c) Some of the solution Q is acidified with concentrated hydrochloric acid. An organic compound, R, forms in the solution. Methanol is added and the mixture warmed, forming a new organic compound S. This mixture is added to sodium carbonate solution in an evaporating basin. A fruity smell is detected. (i) Describe and explain what you would see as the mixture is added to the sodium carbonate solution. (2)(ii) What type of compound is S? (1)*P44884A0416*<br /> (d) The high resolution proton nuclear magnetic resonance (nmr) spectrum of S has only two peaks which are both singlets and have the same area. Deduce the structural formulae of S, R, and P. (3) (Total for Question 2 = 12 marks) *P44884A0516* Turn over<br />

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