3.9 Mixture Separation and Chromatography

Multiple Choice

chromatography separates the mixture of dyes on the basis of their ----------------------------

• density
• solubility
• gravity
• boiling point

Multiple Choice

A pure substance shows ------------------ spot on chromat gram

• 0
• 1
• 2
• 3

Multiple Choice

The diagram below shows a chromatogram obtained when a sample X was analysed together with four other known dyes P, Q, R and S. Dye Q was known to cause cancer. Which of the following dye(s) is/are safe for use?

• P only
• S only
• P and S
• P and X

Multiple Choice

A student extracts the colour from some green smarties and uses paper chromatography to separate components colours. She finds blue has a R_f =0.38 and yellow R_f =0.75 this suggests 

• the yellow is more strongly adsorbed onto the stationary phase and is less solublein the mobile phase.
• the yellow is more strongly adsorbed onto the stationary phase and is more soluble in the mobile phase.
• the blue is more strongly adsorbed onto the stationary phase and is less solublein the mobile phase.
• the blue is more strongly adsorbed onto the stationary phase and is less solublein the mobile phase.

Multiple Choice

A high R_f value indicates strong

• strong affinity to the stationary phase
• strong affinity to the mobile phase
• no affinity to the stationary phase
•  no affinity to the stationary phase