1.1. Unknown organic compound C is analysed by mass spectrometry and infra-red spectroscopy. The mass spectrum is shown in Fig. 2.1 and the infra-red spectrum is shown in Fig. 2.2.

Fig 2.1

Fig 2.2

Deduce one possible identity for compound C. Explain your answer.

 In your answer, use the molecular ion peak at m / e = 55, relevant infra-red absorptions in the region above 1500 cm^-1 and Table 2.1.

Table 2.1

1.2. The mass spectrum of compound C shows an M+1 peak at m / e = 56.

Suggest two ways that this peak could be formed.

1.3. Calculate the expected elemental percentage composition by mass of an 8.0 g sample of compound C. Give your answers to significant figures. 

1.4. Compound C undergoes a reaction to form compound D. The IR spectrum of compound D is shown in Fig. 2.3.

Fig. 2.3

 State the reagents required for this reaction. In your answer, use Table 2.1 and identify any relevant absorptions in the infra-red spectrum to justify your answer.