(4) Zirconium
This element is often used in the chemical production field, and as implants due to its high chemical resistance and stability.
Explanation:
it should be option number (D) Iron (III) oxide
The distance that jet covered in 10 min is 125 Km
calculation
distance = speed x time
speed=750 km/h
time= 10/60hrs
=750 x10/60=125 Km
Answer:

Explanation:
Hello,
In this case, we could considering this as a redox titration:

Thus, the balance turns out (by adding both hydrogen ions and water):

Thus, by stoichiometry, the grams of Fe+2 ions result:

Finally, the mass percent is:

Best regards.