Answer
7.46 g $Na_{2}SO_{4}$
Work Step by Step
Molarity M= 0.350 M
Volume of solution in litre V= 0.150 L
Number of moles of solute n=MV=$0.350M\times.150L= 0.0525 mol$
Mass in grams= n$\times$ Molar mass of $Na_{2}SO_{4}$
$= 0.0525 mol\times142.04 g/mol=7.46 g$