Question

7.51 How many milliliters of 6.00 M HCl solution would be needed to react exactly with 20,0 g of pure solid NaOH? HCl(aq) + NaOH(s) — NaCl(aq) + H2O(C)

Answer 1

Number of moles of NaOH = 20.0 g / 39.997 g/mol = 0.500 mole

From the balanced equation we can say that

1 mole of NaOH requires 1 mole of HCl so

0.500 mole of NaOH will require

= 0.500 mole of NaOH *(1 mole of HCl / 1 mole of NaOH)

= 0.500 mole of HCl

molarity of HCl = number of moles of HCl / volume of solution in L

6.00 = 0.500 / volume of solution in L

volume of solution in L = 0.500 / 6.00 = 0.0833 L

1 L = 1000 mL

0.0833 L = 83.3 mL

Therefore, the volume of HCl needed would be 83.3 mL