Question

An organic compound J has the following percentage by mass, carbon 64.86%, hydrogen 13.51% and the rest is oxygen. The relative molecular mass of the compound is 74. C = 12, O = 16, H = 1)

1. Work out the molecular formula of compound J. 
2. To which homologous series does compound J belong? 
3. Write a balanced chemical equation for the reaction that occurs when compound J reacts with sodium metal. 
4. Name the type of reaction indicated in b(iii) above. 
5. Name the organic compound formed when J reacts with excess acidified potassium managanate (VII).

Answer 1

1. Work out the molecular formula of compound J. 

   	Carbon	Hydrogen	Oxygen
   %	64.86	13.51	100-78.37=21.63
   Moles	64.86/12=5.405	13.51/1=13.51	21.63/16=1.352
   Moles	5.405/1.352=4	13.51/1.352=10	1.352/1.352=1
   Empirical formula	C4H10O	(C4H10O)n =74
   74n=74 n=1

   Molecular formular =C₄H₁₀O
2. To which homologous series does compound J belong? 
   • Alkanols // Alcohols
3. Write a balanced chemical equation for the reaction that occurs when compound J reacts with sodium metal. 
   • 2C₄H₁₀O_(l) + 2Na_(s) 2C₄H₉ONa_(aq) + H_2(g)
4. Name the type of reaction indicated in b(iii) above. 
   • Displacement
5. Name the organic compound formed when J reacts with excess acidified potassium managanate (VII). 
   • Butanoic acid