(i) Chennai is not the capital of Tamil Nadu.

Or

It is false to say that Chennai is the capital of Tamil Nadu.

Or

It is not the case that Chennai is the capital of Tamil Nadu.

(ii) √2 is a complex number.

Or

It is false to say that √2 is not a complex number.

Or

It is not the case that √2 is not a complex number.

(iii) All triangles are equilateral triangle.

Or

It is false to say that all triangles are not equilateral triangle.

Or

It is not the case that all triangles are not equilateral triangle.

(iv) The number 2 is not greater than 7.

Or

It is false to say that the number 2 is greater than 7.

Or

It is not the case that the number 2 is greater than 7.

(v) Every natural number is not an integer.

Or

It is false to say that Every natural number is an integer.

Or

It is not the case that Every natural number is an integer.