Methanoic acid & ethanoic acid have melting(deg. C) & boiling(deg. C) point of 8 & 101; & 17 & 118 respectively. An unknown...
substance, X, melts at around 15 deg. C & boils at around 121 deg. C. Based on data given, what X might be? Explain.
Assuming it has to be either methanoic or ethanoic acid, the most likely answer is ethanoic acid. Both the melting point and boiling point experimental data are closest to the known values for ethanoic acid. The most likely explanation for the slight differences is misreading the thermometer, a thermometer that was not calibrated, or heating the substance too rapidly. If no stirring was taking place during the melting process and/or the boiling process there could have been temperature variations within the bulk of the material that gave the indicated readings.