A is solution Containing 10.10g/dm3 of H2SO4, B Containing NaOH of Unknown Concentration. The volume of acid used is 12.10 cm³ white the Volume of B is 25.0cm3. Calculate;
a. the concentration of A in mol/dm³ a H2SO4
b. the concentration of B in moldm-3
c. the mass of H₂SO4 required to make 10.10g/dm3 of solution
d. the number of hydrogen ion present
Solution
a. Concentration of A( H2SO4 ) in mol/dm3 = ?
Mass conc. of H2SO4 = 10.10g/dm3
Molar mass of H2SO4 = 1 x2 + 32+ 16x 4
= 98g/mol
Conc. of H2SO4 in mol/dm3 = 10.10/98
= 0.103 mol/dm3
b. CA= 0.103moldm-3 CB=? VA= 12.10cm3 VB= 25.0cm3 nA = 1 nB =2
H2SO4 + 2NaOH à Na2SO + 2H2O
CAVA / CBVB = nA /nB
CB = 0.103 X 12.10 X 2 / 25.0 X1
= 0.0997 moldm-3
c. mass of H2SO4 = ?
n = CV(dm3)
= 0.103 x 0.0121
= 0.0012463mol of H2SO4
Molar mass of H2SO4 = 98g/mol
n= mass / molar mass
mass = n x molar mass
= 0.0012463 x 98
= 0.122g of H2SO4
d. H2SO4 -> 2H+ + SO42-
= 2X 0.1030 X 6.02 X 10 23 =1.24X1023 ions of hydrogen
