How many moles of gaseous oxygen at one atmosphere is considered for the reaction with element for plotting a graph in Ellingham diagram?

How many Faradays of electricity is required to produce 4.8 g of Mg at cathode in the electrolysis of molten $\mathrm{MgCl}_2$ ? (Molar mass of $\mathrm{Mg}=24 \mathrm{~g} / \mathrm{mol}$ )

Which of the following compound is highly reactive towards HCN?

What is the range of number of carbon atoms in alkanes found in paraffin wax?