Question

The hydroxide which is soluble in excess of naoh is:

Answer 1

Answer:

If excess sodium hydroxide is added, the precipitate of zinc hydroxide will dissolve, forming a colorless solution of zincate ion: Zn(OH)2 + 2 OH− → Zn(OH)42−.

This property can be used as a test for zinc ions in solution, but it is not exclusive, since aluminum and lead compounds behave in a very similar manner.

Answer 2

Explanation:

Pre-rinse with WFI (water for injection) or PW (purified water) which is performed to wet the interior surface of the tank and remove residue. It also provides a non-chemical pressure test of the CIP flow path. Caustic solution single pass flush through the vessel to drain. Caustic is the main cleaning solution.