Correct option is (b) 11.9
Easy explanation: 98% (v/v) means 98 mL of acid is present in 100 mL of solution.
In 650 mL of solution, volume of acid present = 0.98 x 650 mL = 637 mL
Mass of acid present = volume x density = 637 mL x 1.83 g/mL =1165.71 g
Molar mass of sulfuric acid (H2SO4) = (2 x 1 + 32 + 4 x 16) = 98 g/mole
Number of moles of sulfuric acid = mass/molar mass = 1165.71g/(98 g/mole) = 11.9 moles.