Calculate rate constant of a first order reaction having half life $1$ minute $40$ second?

In a reaction,
$2\text{N}_2\text{O}_{5(g)} \rightarrow 4\,\text{NO}_{2(g)} + \text{O}_{2(g)}$
$\text{N}_2\text{O}_5$ disappears at a rate of $0.06$ mol dm$^{-3}$ s$^{-1}$
Calculate rate of formation of $\text{O}_{2(g)}$ ?

Identify the term used to describe movement of colloidal particles under applied electric potential without using semipermeable membrane.

Which element from following has highest melting point?