| Halogenoalkane | Precipitate Color | Rate of Precipitation | Bond Enthalpy (C-X) | |---|---|---|---| | Fluoroalkane | No precipitate (AgF soluble) | Very slow (usually not seen) | Very high (484 kJ/mol) | | Chloroalkane | White (AgCl) | Slow (minutes, needs warming) | 338 kJ/mol | | Bromoalkane | Cream (AgBr) | Faster (seconds to minutes) | 276 kJ/mol | | Iodoalkane | Yellow (AgI) | Instant (room temperature) | 238 kJ/mol |
This is a slower, less vigorous reaction than with OH⁻. reactions of halogenoalkanes 1 chemsheets answers exclusive
They often ask: “Why is KCN dissolved in ethanol rather than water?” Answer: Water would solvate the CN⁻ nucleophile too strongly (via hydrogen bonding), reducing its nucleophilicity. Ethanol provides a polar medium but leaves the CN⁻ “naked” and more reactive. | Halogenoalkane | Precipitate Color | Rate of