According to molecular orbital theory which of the following statement about the magnetic character and bond order is correct regarding $$O_2^+$$

A sodium salt on treatment with MgCl₃ gives white precipitate only on heating. The anion of the sodium salt is

The value of the integral $$\int\limits_0^1 {\sqrt {{{1 - x} \over {1 + x}}} dx} $$ is

If $$f(x)$$ is differentiable and $$\int\limits_0^{{t^2}} {xf\left( x \right)dx = {2 \over 5}{t^5},} $$ then $$f\left( {{4 \over {25}}} \right)$$ equals