The true statement about the directrix is that each directrix of this ellipse is 31.25 units from the center on the major axis.
<h3>How to determine the distance of the directrix?</h3>
The equation of the ellipse is given as:
The above means that:
a^2 = 625
a = 25
b^2 = 225
b = 15
Calculate c using:
c^2 = a^2 - b^2
This gives
c^2 = 625 - 225
Evaluate the difference
c^2 = 400
Evaluate the square root
c = 20
The equation of the directrix is
x - x₀ = ± a²/c
So, we have:
x - x₀ = ± 625/20
Evaluate the quotient
x - x₀ = ± 31.25
This means that, each directrix is 31.25 units from the center on the major axis.
Read more about directrix at:
brainly.com/question/26109874
The only reaction that will most likely take place based on the activity series is; C: Ba + Na₂CO₃
<h3>Activity Series</h3>
From the activity series given, we can say that during a displacement reaction, the more reactive metal will always displace the lesser reactive metal from a compound.
Let us look at each of the given options;
A) Ag + FeCl₃
From the activity series, Silver(Ag) is less reactive than Iron(Fe) and as such Silver cannot displace iron from its' compound.
B) Zn + CaO
Zinc (Zn) is a less reactive metal than Calcium (Ca), so it cannot cannot displace Calcium from its' compound.
C) Ba + Na₂CO₃
Barium (Ba) is a more reactive metal than Sodium (Na), and therefore Barium will displace sodium from its compound in a displacement reaction.
D) Cr + KNO₃
Chromium (Cr) is a lesser reactive metal than Potassium (K), and it therefore cannot displace Potassium from its compound.
Complete question is;
Which reaction will most likely take place based on the activity series? Li > K Ba > CaNa > Mn > Zn > Cr> Fe> Cd Ni > H > Sb > Cu > Ag > Pd > Hg > Pt
A. Ag + FeCl₃
B. Zn + CaO
C. Ba + Na₂CO₃
D. Cr + KNO₃
Read more about Activity Series at; brainly.com/question/17469010
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