(i) A chord of a circle is a line whose two end points lie on the circle and all the points on the line lie inside the circle. So, the radius of a circle is not a chord of the circle.Thus, the given statement is false.
(ii) The centre of a circle bisects chord of circle when the chord is diameter of circle. When the chord is other than diameter then centre of circle does not lie on the chord. Thus, the given statement is false.
(iii) In the equation of an ellipse if we put a = b, then we get an equation of circle.
Thus, the given statement is true.
(iv) It is given that x, y ∈ Z such that x > y.
Multiplying both sides by negative sign, we have
x, y ∈ Z such that –x < –y.
Thus, the given statement is true.
(v) Since √11 cannot be expressed in the form

a

b

, where a and b are integers and b ≠ 0. Thus, the given statement is false.