Which of the following is not correct?

The interaction between $$\pi$$ bond and lone pair of electrons present on an adjacent atom is responsible for

In which one of the following metal carbonyls, $$\mathrm{CO}$$ forms a bridge between metal atoms?

$$\mathrm{KMnO}_4$$ decomposes on heating at $$513 \mathrm{~K}$$ to form $$\mathrm{O}_2$$ along with