A25.0-ml sample of an h2so4 solution requires 50.0 ml of 0.150 m naoh to completely react with the h2so4. what was the concentration (molarity, m) of the h2so4 solution?
h2so4(aq) + 2 naoh(aq) à na2so4(aq) + 2 h2o(l)

V( H₂SO₄) = 25.0 mL in liters = 25.0 / 1000 = 0.025 L
 M(H₂SO₄) = ?

V(NaOH) = 50.0 mL = 50.0 / 1000 = 0.05 L 
M(NaOH) = 0.150 M

number of moles NaOH :

n = M x V

n = 0.150 x  0.05 

n = 0.0075 moles of NaOH 

H₂SO₄(aq) + 2 NaOH(aq) = Na₂SO₄(aq) + 2 H₂O(l)

1 mole H₂SO₄ 2 mole NaOH
? mole H₂SO₄  0.0075 moles NaOH

moles = 0.0075 * 1 / 2

= 0.00375 moles of H₂SO₄

M(H₂SO₄) = n / V

M = 0.00375 /  0.025

= 0.15 M

hope this helps!

The correct answer is "atomic weight".

You use the atomic number to find out how many protons and neutrons there are in the atom. you use the atomic mass to find out how many protons and electrons there are in the atom.