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| Question | Answer |
| Benzene properties | Characteristic odour Immiscible in water \(C_6H_6\) colourless liquid High C:H ratio |
| 2 pieces of evidence against the Kekule structure | 1) Substitution and addition reactions do not occur easily like in alkenes. Thermochemical evidence H formation is less positive than expected suggesting it is more stable than the proposed structure. |
| What does the difference between enthalpy of hydrogenation of cyclohexene and benzene show? | The energy taken in to overcome the stable benzene resonance structure. |
| What is the bond length in benzene? | 0.139nm |
| Describe the arrangement of electrons in benzene | Each C forms a sigma bond with adjacent C atoms forming a planar carbon hexagonal skeleton. Each C then has 1 p orbital containing 1 electron and the orbital lobes fuse to form 2 areas of delocalised electron density above and below the carbon skeleton. |
| What do you see when benzene is burnt in air? | A smoky yellow flame |
| Benzene with bromine in UV is what type of reaction? | Free-radical addition |
| What do halogen carrier catalysts do to \(Br_2\) molecules? | Polarise it |
| Does benzene react with conc nitric acid on its own? | No |
| Which is a stronger acid sulphuric or nitric? | Sulphuric |
| Temperature conditions for nitration of benzene | Below 55\(\omicron\) |
| Method for nitrating benzene | Add benzene dropwise from a tap funnel to nitrating mixture in a cold flask. |
| What occurs when nitrating benzene if the temperature rises above 55? | Multiple substitution |
| Properties of nitrobenzene | Toxic Flammable Pale yellow Liquid Aromatic Odour of bitter almonds |
| What is fuming sulphuric acid? | Conc. sulphuric with additional \(SO_3\) |
| Name of mechanism for and conditions of alkylation and acylation | Electrophillic substitution Reflux |
| What type of reactions are acylation and alkylation called? | Friedel Craft's reactions |
| Conditions for addition of \(H_2\) to benzene | Raney Ni cat 150 degrees |
| Benzene activated and non-activated positions | 2,4,6 = activated 1, 3, 5 = non-activated |
| Does OH activate the ring? | Yes |
| What colour and state is 2, 4, 6 - tribromophenol? | Solid white |
| Phenol reacts with dilute nitric acid? | Yes |
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