A simply because of I'm a pretty good guesser, Hope this helps.
Answer : (4) Chromatography
Explanation :
Chromatography : It is a separation technique of a mixture by passing it through a medium in which components travels at different rates.
There are many types of chromatography but this is paper chromatography.
Paper chromatography : It is used to separate the colored substances. In paper chromatography, water is the mobile phase and paper is the stationary phase. The mixture of components moves at different speeds through the stationary phase so that they can be separated.
In paper chromatography, several colors can be separated based on their solubility. The more soluble a color is, the more readily it will dissolve in mobile phase and farther it will travel.
I’m gonna guess equal force sorry if I get it wrong <3
It is easier to determine this if we draw the structural formula of lactic acid as shown in the attached picture. There are three functional groups in lactic acid: carboxyl group, hydroxyl group, and the parent alkane chain. Any of the hydrogens in the alkane chain is the least acidic. Then, it is followed by the H in the hydroxyl group. The most acidic is the H in the carboxyl group.