Suppose that a TLC plate is spotted with samples 1.0 cm above the bottom of the plate. Select the consequence of inserting the plate into a developing chamber containing a pool of developing solvent that is 1.2 cm deep (a) The compounds in the samples will leach into the pool of developing solvent resulting in poor resolution.

(b)The pencil marks will dissolve into the developing solvent.

(c)The increased capillary action will cause the compounds to migrate up the plate more quickly.

(d)The increased depth of developing solvent will result in better resolution of the compounds in each sample.

The compounds in the samples will leach into the pool of developing solvent resulting in poor resolution.

Explanation:

The aim of thin layer chromatography is the separation of a mixture. Usually, the stationary phase is spotted with the mixture. A mark is made with a pencil at the point to be spotted.

It is necessary to note that the solvent must be below the spot where the mixture is. This is because, if the solvent is above the spot of the mixture to be separated, the components of the mixture will dissolve away in the solvent resolution in poor separation. This is exactly what will happen when the sample is spotted at 1.0 cm above the bottom when the solvent is 1.2 cm above the bottom.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.