Question

11. Why should you use pencil instead of pen when marking on a thin layer chromatography plate?

a. Pencil lead isn't as dark.

b. The components of pen ink will separate along with your sample, while pencil lead will not.

c. Pen ink will not mark on a TLC plate.

d. Pen ink will undergo a chemical reaction with the solvent.

12. Which of the following is not a reason to use thin-layer chromatography?

a. To determine the number of components in a mixture

b. To monitor the progress of a reaction

c. To monitor column chromatography

d. To remove impurities from your compound

Answer 1

11- A Thin Layer Chromatography plate is used in chromatography. Chromatography is to separate components of a dye. The reason why we use pencils instead of pen is because pencils are made of lead, Inks in pens contains dyes that might affect the chromatogram as inks has dyes that can potentially separate while doing chromatography. Lead is less likely to seperate during chromatography. So in order to make the experiment more accurate, we use usually use pencils to mark.

Hence Option b

According to Chegg Guidelines when there are more than one question we should solve only the first one.

Hopefully you understand this and ask the other question is a separate question.

If you found the answer useful please do upvote,it really helps.