Answer:
Here's what I get
Step-by-step explanation:
The etching gel used in many dental procedures contains
- 10 % to 50 % phosphoric acid in water
- a thickening agent consisting of hydrocarbon polymers and a colloidal silica sol
- a colouring agent such as cobalt aluminate blue spinel (CoAl₂O₄) to make it visible on a tooth.