How many grams can be oxidized. Help me out, please. ?

Question

How many grams of K2SO3 can be oxidized to K2SO4 by 7.90 g of KMnO4, which will be reduced to MnO2?

Answer 1

3 SO32- + 2 MnO4- + 2H+ >> 3 SO42- + 2MnO2 + H2O

Moles KMnO4 = 7.90 / 158.04 g/mol =0.0500

Moles K2SO3 = 0.500 x 3 / 2 =0.075

Mass K2SO3 = 0.075 mol x 158.3 g/mol =11.9 g