The correct order of bond orders of $${C_2}^{2 - }$$, $${N_2}^{2 - }$$ and $${O_2}^{2 - }$$

At 25$$^\circ$$C and 1 atm pressure, the enthalpies of combustion are as given below :

The enthalpy of formation of ethane is

For a first order reaction, the time required for completion of 90% reaction is 'x' times the half life of the reaction. The value of 'x' is

(Given : ln 10 = 2.303 and log 2 = 0.3010)

Metals generally melt at very high temperature. Amongst the following, the metal with the highest melting point will be :