Question

question 18
1 pts
in the nitrate testing if the broth turns red after the addition of zn powder, it represents a positive result for nitrate reduction. true or false?
true
false

Explanation:

In nitrate reduction testing, if the broth is colorless after adding reagents (N1, N2) and turns red after adding Zn, it means nitrate was not reduced (Zn reduces nitrate to nitrite, causing the red color—so this is a negative result for bacterial nitrate reduction, as the bacteria didn't reduce nitrate; a positive result for bacterial reduction would be colorless before Zn, meaning nitrate was reduced by bacteria, and Zn doesn't cause a color change then). So the statement is false.

Answer:

False