1)

a) mm ( NaOH ) = 23 + 16 + 1 = 40 g/mol

M = m / mm x V

M = 20 / 40 x 2

M = 20 / 80

M = 0,25 mol/L

b)

M = n / V

M = 3 / 3

M = 1,0 mol/L


c)

mm ( HCl) = 1 + 35,5 = 36,5 g/mol

M = m / mm x V

M = 73 / 36,5 x 4

M = 73 / 146

M = 0,5 mol/L


d)
 
mm ( C₁₂H₂₂O₁₁) = 12 x 12 + 1 x 22 + 16 x 11 = 342 g/mol

2000 cm³ / 1000 = 2 L

M = m / mm x V

M = 684 / 342 x 2

M = 684 / 684

M = 1,0 mol/L


espero ter ajudado!