Can anyone me with this problem? i’m begging you.

First off, we need to write out the balanced chemical equation for this reaction (include states too!),

2NaOH(aq) + H2SO4(aq) --> Na2SO4(aq) + 2H2O(l)

We are given that NaOH is 210g

Figure out the moles,

n=m/M
  =210 / 2(22.99) + 2(16) + 2(1.008)
  =2.625...

Now look back at the chemical equation, the mole ratio from NaOH and Na2SO4 is 2:1

So divide the moles of NaOH by 2 to get the moles of Na2SO4

You get, n=1.312...

Use n=m/M again to find the mass of Na2SO4

1.312.. = m / 2(22.99) + 32.06 + 4(16)
m = 1.312.. x (2(22.99) + 32.06 + 4(16)) 
    = 186.4g (1 d.p)

Therefore, mass of Na2SO4 (sodium sulfate) is 186.4g

HOPE THIS HELPED!

The answer is c. 320 g