What volume of 0.25 M hydrochloric acid is required to react completely with 40 mL of 0.50 M calcium hydroxide? - 40 mL - VCE - SSCE Chemistry - Question 7 - 2014 - Paper 1

The balanced chemical reaction for the neutralization of calcium hydroxide with hydrochloric acid is:

$$Ca(OH)_2 + 2 HCl ightarrow CaCl_2 + 2 H_2O$$

From the reaction, it is clear that 1 mole of calcium hydroxide reacts with 2 moles of hydrochloric acid. Therefore, to find the moles of hydrochloric acid needed:

$$ext{Moles}_{HCl} = 2 imes ext{Moles}_{Ca(OH)_2} = 2 imes 0.020 = 0.040 ext{ moles}$$

Now we can calculate the volume of 0.25 M hydrochloric acid necessary to provide 0.040 moles:

Using the formula:

ext{Volume} = rac{ ext{Moles}}{ ext{Concentration}} = rac{0.040}{0.25} = 0.160 ext{ L}

Converting to mL gives:

$$0.160 ext{ L} = 160 ext{ mL}$$

Thus, the answer is 160 mL.