Question

A closed vessel is found to contain 1g of Mg and 0.5g of oxygen. The mixture is burnt. How many mL of M/4 solution of H2SO4will dissolve the residue in the vessel?​

Answer 1

Answer:

Balanced reaction is:

2Mg+O /2 →2MgO

According to the reaction 2 mol (or 2×24.3=48.6g) Mg reacts with 32 g oxygen. 1 g of Mg requires = 48.6/32

=0.66g oxygen but given oxygen is 0.5 g ∴ oxygen is the limiting reagent

0.5 g oxygen can burn == 32/48.6 ×0.5=0.75g Mg

Excess of Mg left =1−0.75

=0.25g

Hope it helps!