Question

50mL of 0.100M sulfuric acid neutralizes 25mL of which of the following?

Answer 1

Thw neutralization reaction will be,

H2SO4+2OH- --> SO4^2- + 2H2O

So we see that, to neutralize 1 H2SO4 we would need 2 OH-.

Now, let us calculate the moles of H2SO4 we have,

given data,

molarity of H2SO4 = 0.100 M

volume of H2SO4 = 50 mL = 0.05 L

Thus,

moles = molarity x L

           = 0.1 x 0.05

           = 0.005 moles

So we would need 0.01 moles of OH- to neutralize this acid.

Let us calculate moles of,

(1) 25 mL of 0.1 M NaOH

moles = 0.025 x 0.1

           = 0.0025 moles

It has 1 OH- in 0.0025 moles of NaOH

(2) 25 mL of 0.1 M of Sr(OH)2

moles = 0.1 x 0.025

           = 0.0025 moles

It has 2OH- in 0.025 moles of Sr(OH)2

(3) 25 mL of 0.2 M of Sr(OH)2

moles = 0.2 x 0.025

           = 0.005 moles

It has 2OH- in 0.025 moles of Sr(OH)2

(4) 25 mL of 0.2 M KOH

moles = 0.025 x 0.2

           = 0.005 moles

It has 1 OH- in 0.005 moles of KOH

(5) 25 mL of 0.4 M Ca(OH)2

moles = 0.025 x 0.4

           = 0.01 moles

So as we can see, option (5) onlt gives the exact moles of OH- required to neutralize the given H2SO4 solution. Ths the answer will be,

(5) 0.4 M Ca(OH)2

will neutralize 50 mL of 1M H2SO4