b) A chemical salt gave the following percentage composition: Na = 29.11%, S = 40.51% and O = 30.38%.
Calculate the empirical formu;a of the salt. [Na = 23, S = 32, O = 16].

c) 4.92g of hydrated magnesium sulphate $(MgS{O}_4.x{H}_{2}O)$ on strong heating leaves 2.40g of anhydrous magnesium sulphate. Calculate the value of x in $MgS{O}_4.x{H}_{2}O . [Mg=24, S=32, O=16, H=1]$